Investigating a Suspected meteotsunami along the Northwest Coast of Ireland in February 2022

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This phenomenon resembled that of a meteotsunami, an atmospherically driven sea-level anomaly. This study provides context surrounding the origin and classification of the event via the use of high-frequency tidal data, atmospheric pressure data, and wind speed records from nearby tidal and weather stations. A rapid shift in atmospheric pressure following Storm Franklin, and the occurrence of a high tide matched the timing of the event. However, neither the tidal nor the wind conditions were extreme at this time suggesting the event was not a strong astronomical tide or storm surge. The absence of seismic and volcanic activity inferred it was not a traditional tsunami. The aligned timing of the video, the sudden increase in atmospheric pressure rate, the movement of the jet stream over Ireland, and the sea-level anomalies point to a meteotsunami. Improvements in public awareness and monitoring are crucial to our understanding of these events, and to our ability to mitigate the risks associated, especially under our changing climate. meteotsunami sea-level anomalies atmospheric pressure jet stream Lough Swilly Ireland Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction At 08:50 UTC on the 21st of February 2022, a video was captured and posted on Twitter (now X.com) titled “A rather unusual storm surge this morning” (Fig. 1 ). The recording of such phenomena in recent years has raised public awareness of unusual sea-level related events in Ireland (McCarthy and Berry 2022 ) and has increased the consciousness of the associated hazard. The video shows a propagating wave travelling inland from a sea inlet and flooding the Golf Course of Portsalon next to Lough Swilly, Co Donegal, Ireland. The phenomenon resembled that of a meteotsunami or other extreme disturbance such as a tidal bore or extreme seiche. Meteotsunamis typically result from rapid atmospheric pressure shifts, often linked to storms, fast-moving weather systems, or winds (NOAA 2023a ; Vilibic and Šepic 2017). In February 2022, in the week preceding the video, Ireland was struck by three named storms: Storm Dudley on the 16th, Storm Eunice on the 18th, and Storm Franklin on the 20th (Met Eireann 2023). This was attributed to the presence of a highly active North Atlantic jet stream flowing towards Ireland during that period (Met Eireann 2022 ). Storms can generate ocean waves that travel at a similar speed to a pressure wave resulting in Proudman resonance and the formation of a meteotsunami (NWS 2015 ). As they reach the coast, meteotsunamis alter water levels similar to seismic tsunamis, causing rapid drops followed by sudden rises (Lewis et al. 2023 ). Both share a high frequency of 2 minutes to 2 hours (Kim et al. 2022 ). Most meteotsunamis go unnoticed or are misclassified, especially in winter during unsettled weather (NOAA 2023a ). However, stronger events can cause severe flooding and fatalities, influenced by pressure disturbance magnitude, shelf depth, and coastline shape (Renzi et al. 2023 ). The occurrence of meteotsunami events in Irish waters is common and these events tend to be some of the largest meteotsunamis experienced across north-western Europe (Williams et al. 2021 ). One such event occurred on the 18th June 2022 and was observed across the whole of the south coast of Ireland and southern Wales (McCarthy and Berry 2022 ; Sibley 2022 ). Public awareness of this was high due to filming of the unusual event, which stood out due to otherwise calm conditions. A meteotsunami is not the only possible explanation for the videoed event. The event occurred on the approach to high tide, which is unusual for meteotsunamis but is the most common time for tidal bores. Tidal bores are wave phenomena that form due to the unbalancing of the hydrodynamic system. They require a large tidal range, and their development relies on the convergence and/or divergence of the major tidal constituents and is further amplified by other factors such as ocean basin geometry (Chanson 2009 ). The combination of independent conditions like the occurrence of large tides and low river discharge has been associated with tidal bores (Martinius and Gowland 2010 ). Tidal bores are famous in certain locations, such as on the Severn Estuary; however, they are not well known on Lough Swilly. Due to the proximity of several named storms, there is a potential that this was a storm surge event. Storm surges are defined as the anomalous escalation in seawater level during a storm. Storm surges are calculated as the height of the water level exceeding the astronomical tide (NOAA 2023b ). Storm surges in Irish waters are typically greater along the west coast compared to the east coast due the prevailing origin of Atlantic Storms from the west and the open geography of the west in comparison to the more sheltered Irish Sea (Olbert and Hartnett 2010 ). They typically occur on longer timescales than meteotsunamis and tidal bores and are not usually associated with wave-like phenomena. However, there is the possibility that storm Franklin triggered extreme seiching in Lough Swilly or a freak wave. Seismic tsunamis are infrequent in Irish waters but do remain in popular consciousness. The last major tsunami to hit Irish waters and affect the island of Ireland was the 1755 Lisbon tsunami, which was generated by a massive earthquake of magnitude 8.5–9 (Mendes-Victor et al. 1994 ). This tsunami hit the coast of Ireland and saw the creation of an island out of Aughinish, south of Galway Bay, and severely damaged Galway’s Spanish Arch located within Galway Harbour (Giles et al. 2020 ; Kearns 2020 ). Tsunamis can also be formed by the occurrence of a volcanic eruption. The Hunga-Tonga Volcanic eruption that occurred in January 2022 sent powerful atmospheric and oceanic disturbances around the globe which caused both tsunamis and meteotsunamis (Villalonga et al. 2023 ). Submarine landsides have also been known to cause tsunamis in the past. In 1998, Papua New Guinea was devastated by a 15-metre-high tsunami which was attributed to a sudden shift in the seabed off the northern coastline (Tappin 2017 ). This study contextualises and describes the event that featured in the video from the 21st February 2022, collates available meteorological and sea-level observations to describe the wider context and assesses whether this extreme event is likely due to meteotsunami, tidal bore, or other disturbance. 2. Methods 2.1. Sea-Level Data Tidal data was collected from two separate sources, the OPW’s HYDRO-DATA interactive map (OPW 2025 ) and from the Marine Institute’s Real Time Tidal Observations (Marine Institute 2022a ). In total six tidal stations: Malin Head, Letterkenny, Aranmore Island, Killybegs, Enniscrone and Ballyglass (Fig. 2 ), located along the northwest coast of Ireland provided 5-minute high frequency data that was used in this analysis. All stations are fully tidal, except for Letterkenny, which is heavily fluvial, being situated at the head of Lough Swilly on the River Swilly. To avoid the possibility of false tidal readings, the Newmills water level station located further upstream was analysed and the results were compared to the Letterkenny tidal data. Tidal harmonics were fitted to the fully tidal stations over timeperiods of at least 1 year, using the TideHarmonics package in R, fitting at least 64 tidal constituents to ensure goodness of fit. 2.2. Wind Speed and Pressure Atmospheric data from weather stations were provided by Met Eireann (Met Eireann 2024) and gathered from the Marine Institute’s Marine Data Buoy Observation Network (Marine Institute 2022b ). The 1-minute high frequency Met Eireann data provided wind speed data and atmospheric pressure data from 00:00:00 on the 19th February 2022 to 23:59:00 on the 22nd February 2022 at Mace Head (not shown), Markree Castle, Malin Head, Finner, and Belmullet (Fig. 2 ). This was joined with the Marine Institute’s ocean buoy wind speed measured from the M4 station. 2.3. Seismic and Volcanic Data Earthquake observations from the USGS Earthquake Hazards program and reports of volcanic activity from the Smithsonian Institution’s Global Volcanism Program provided insight into whether the videoed event could have been seismic in nature. On the 21st of February 2022, only two magnitude 6 or higher earthquakes occurred around the globe. The first occurred in the Southern Ocean off the coast of the Balleny Islands, Antarctica. The second occurred in the northwestern tip of Argentina. Volcanic activity was reported on the 21st of February 2022. Sangeang Api volcano in Indonesia began to release ash plumes on the 17th and continued until the 22nd (Smithsonian Institution n.d.). Due to the remoteness of these events, a seismic tsunami was ruled out and no further analysis was conducted on this hypothesis. 3. Results 3.1. Sea-level fluctuations in Lough Swilly Figure 3 shows the evolution of sea-level in Lough Swilly at Letterkenny (head of the sea lough) and Malin Head (mouth of the sea lough) over the 19th to the 22nd of February. Storm Franklin’s path crossed the north Atlantic as it moved between the south coast of Iceland and the north coast of Ireland before tracking southeast over Scotland and approaching the Netherlands. The lowest pressure recorded within the eye of Storm Franklin was 952 hPa at 9am on the 20th of February when the storm was located directly off the south coast of Iceland. The closest the storm’s eye got to Ireland occurred between 9pm on the 20th and 3am on the 21st, with a pressure of between 963 hPa and 974 hPa. By the time the videoed event was recorded, the remains of storm Franklin’s eye were located closer to the Netherlands than Ireland. At this time, mean sea-level pressure at risen to 983 hPa. Heavy rainfall was associated with the Storm Franklin, which raised river levels in the River Swilly resulting in a notable fluvial event on the 20th where, at low tide, levels at Letterkenny rose to nearly 2 m above expected levels (Fig. 3 , pink ). Winds rose across the northwest of Ireland as the storm transited, with a notable increase in non-tidal variability evident at Malin Head from mid-morning on the 20th. A positive storm surge developed with the passing of Storm Franklin, peaking close to low tide on the morning of the 21st. This positive surge rapidly reversed following the passage of Storm Franklin, with non-tidal water levels dropping by approximately 1 m between successive low tides on the 21st . At the time of the event at 08:50 UTC, the tide was nearly at its maximum. This tidal magnitude was not extreme or unusually high and did not occur in conduction with a spring tide. Compared to the 20th and 19th, the tidal range was decreasing ahead of the occurrence of a neap tide on the 23rd. The event does not stand out in comparison to previous days where larger non-tidal anomalies were experienced. 3.2. Non-tidal sea-level fluctuations High levels of non-tidal sea-level fluctuations were observed across tidal stations in the northwest of Ireland. The rapid and unpredictable shifts in non-tidal sea-level began to occur just before 12pm on the 20th and did not appear to fully subside until the end of the 21st in most stations (Fig. 4 ). The maximum sea-level anomalies recorded were 0.818 m at Killybegs (20th, 6:15 UTC), 0.743 m at Aranmore Island (21st, 00:25 UTC), 1.005 m at Enniscrone (21st, 06:10 UTC), 1.507 m at Malin Head (21st, 03:35 UTC), and 0.415 m at Ballyglass (21st, 02:05 UTC). Significant shifts in the 40-minute rolling standard deviation also begin to appear before 12:00 UTC on the 20th across all the stations and does not appear to fully return to normal levels in most stations by the 22nd. At the time of the event, non-tidal levels were falling. 3.3. Atmospheric Conditions Atmospheric pressure data across 5 weather stations recorded a pressure increase of between 26.6–28.4 hPa over the 24-hour period between 12:00 UTC on the 20th and 12:00 UTC on the 21st. The first 12 hours saw a pressure rate increase of between 0.191 hPa/h and 0.975 hPa/h. The second 12-hour period saw a dramatic increase in the rate of atmospheric increase of between 1.24 hPa/h and 2.15 hPa/h. The two weather stations furthest north, Finner and Malin Head had the lowest pressure increase per hour during the first 12 hours, but had the highest pressure increase per hour during the second 12 hours (Fig. 5 ). Mace Head, a coastal weather station south of the area pictured in Fig. 2 , experienced an increase in pressure that exceeded 1005 hPa in the early hours of the 21 st . 40 minutes later, the Belmullet station exceed 1005 hPa. Several hours later, the pressure wave arrived at Markree Castle, followed shortly after by Finner and then lastly the 1005 hPa threshold was exceeded at Malin Head (furthest north) just minutes after the videoed event occurred. This same period was when atmospheric pressure was increasing at its highest rate (2.4 hPa/h) at Malin Head. The rate of pressure increase from the M4 buoy was very similar to that of the onshore weather stations. In the first 12 hours, pressure rate increase was 0.575 hPa/h, and in the second 12 hours it followed the significant positive trend set by the onshore stations, measuring 1.791 hPa/h. Across several weather stations located along the western coast of Ireland, wind speeds of over 60 kph were recorded towards the end of the 20th and in the early hours of the 21st of February 2022 (Fig. 6 ). The highest wind speed recorded at the ‘M4’ buoy was just over 35 kph in the early hours of the 21st. At the time of the videoed event, wind speeds observed at the closest weather station to Portsalon golf club, the Malin Head weather station, had dropped to around 40 kph. 4. Discussion Based on the videographic evidence from Fig. 1 a significant water level event occurred on the morning of the 21st February at Portsalon golf club. Besides the original video, no other evidence of ‘unusual’ sea-level activity was reported. Based on our analysis here, the conditions on the morning of the 21st of February were not unusual in comparison to those since the arrival of Storm Franklin. Similar events may well have occurred but not have been recorded. Based on the tracking of Storm Franklin’s eye, the north and west of Ireland was the location of a storm surge event between 9:00 UTC on the 20th and 03:00 UTC on the 21st, during which Storm Franklin was the closest to the Irish landmass. However, at 09:00 UTC on the 21st, the remains of Storm Franklin’s eye was closer to the Netherlands than it was to Ireland, non-tidal sea-levels were falling, and the most severe weather conditions associated with the storm were past at Portsalon Golf Club. Wind speed data supported this observation, with peak speeds recorded across stations from 9:00 UTC on 20th February to 03:00 UTC on 21st February. A relatively significant drop off in wind speed occurred after this time, with a wind speed of 40 kph recorded at the Malin Head weather station around 09:00 UTC on the 21st, which is the average for that time of year. This suggests a storm surge event would be unlikely the driver of the filmed event. A high tide did coincide with the timing of the videoed event. However, the tides magnitude was not classified as extreme or unusually high and did not occur in conduction with a spring tide. Compared to the 20th and 19th, the tidal range was decreasing ahead of the occurrence of a neap tide on the 23rd. The moon was not especially close to the earth on the 21st, which suggests the videoed event was not a result of the perigee or any astronomical tide anomaly. Tidal data from the Letterkenny tidal station showed very large non-tidal fluctuations on February 20th. At low tide, a sudden increase in water level was observed. However, this occurred well over a day before the videoed event was recorded. The analysis of water level data from a further upstream river station, Newmills, showed what appeared to be a rapid and significant influx of water into the river system prior to the increase observed in Letterkenny. Associated with the arrival of Storm Franklin, a heavy precipitation event occurred, causing the influx of water into the river system and influencing the tidal data of the Letterkenny station. However, this had abated by the time of the event on the 21st and was therefore not likely linked. Observation from Letterkenny tidal station provides possible evidence that the filmed phenomenon could have been an unusual seiching event during high tide. Low-pass filtered data (10 minute) from Malin Head may also present signs of seiching at high tide, however it is difficult to discern. Buncrana tidal station, also located in Lough Swilly, was not active at the time of the event, but, since its installation in November 2024, has not observed a comparable signal of high tide seiching. As no in-situ tidal station exists at Portsalon, or indeed at any location on the western shore of Lough Swilly, confirmation of a seiching event is difficult. Tidal data across other stations across the northwest of Ireland showed very similar water level anomalies beginning to occur before 12:00 UTC on the 20th. The anomalies are first seen in Malin Head and propagate further south reaching Ballyglass last. The Malin Head station did see the greatest single anomaly, however it occurred after all but one of the other stations observed their maximum anomalies. A possible reason for this is the shape of the coastline directly affecting the intensify of the sea-level anomaly at each station ( Rabinovich 2020 ). A secondary propagation was also hypothesised, one based off the timing of the videoed event. This propagation suggested that there was an almost 180-degree shift in the direction of the triggering factor, occurring in the early hours of the 21st. Using this propagation, Ballyglass receives the first sea-level anomalies followed by Enniscrone, Aranmore and then Malin Head. Based off this timeline, further analysis into whether the videoed event could be observed across the other stations, and what magnitude the sea-level anomalies were conducted. Results from the analysis of the atmospheric pressure data also suggests a change occurred during the early hours of the 21st. The rate of atmospheric pressure increase before 00:00 UTC on the 21st was relatively low across all the stations, ranging from 0.191 hPa/h to 0.975 hPa/h. However, after 00:00 UTC on the 21st, rates of atmospheric pressure increase rose dramatically, ranging from 1.24 hPa/h to 2.15 hPa/h. Figure 5 depicts this slow increase of pressure across the northwest of Ireland before the occurrence of a sudden and rapid shift in the rate of atmospheric pressure increase. Using the south to north propagation derived from the videoed event’s timeframe, sea-level anomalies and atmospheric pressure increases over one-hour periods were linked. The Belmullet weather station measured an increase of 2 hPa from 03:00 to 04:00 UTC on the 21st. This timeframe matched the period in which Ballyglass tidal station observed a sea-level anomaly of 0.389 metres. The Malin Head weather station measured an increase of 2.4 hPa from 08:50 to 09:50 UTC on the 21st. This timeframe matched the period in which Malin Head tidal station observed a sea-level anomaly of 0.501 metres. Based on these results, it appears that a significant atmospheric pressure increase might have caused these sea-level anomalies, and this suggests the videoed event could have been a meteotsunami. Similar rates of pressure change were observed during the 18th June 2022 meteotsunami event that affected the south coast of Ireland (McCarthy and Berry 2022 ). A possible explanation as to what caused the observed shift in propagation and sudden increase in atmospheric pressure rates after 00:00 UTC on the 21st exists within the strength and positioning of the jet stream over Ireland. As the tidal data began to show unusual oscillations just before 12:00 UTC on the 20th, the jet stream had been moving towards Ireland, influencing the northwest first before covering the rest of Ireland by 12:00 UTC. This would coincide with the slight north to south propagation experienced within the sea-level anomalies before 00:00 UTC on the 21st. Between 12:00 UTC on the 20th and 00:00 UTC on the 21st, the jet stream gradually moved towards the south, resulting in the northwest coast falling outside its influence. After 00:00 UTC on the 21st, the jet stream’s fastest winds began to move back across the country from the southwest to the northeast. This second propagation coincides with the occurrence of the videoed event and the rapid increase in atmospheric pressure from south to north. These observations suggest the jet stream had a significant role in the creation and distribution of atmospheric pressure conditions that were suitable for the formation of sea-level oscillations linked to meteotsunami events. During the June 18th southern Ireland meteotsunami event, the jet stream was only present over the affected area of the south coast, highlighting its role in producing meteotsunami events (Renzi et al. 2023 ). Proudman resonance is the typical mechanism to amplify the magnitude of meteotsunamis. Considering the depth of the continental shelf off the coast of Donegal is between 20–40 metres closest to the shoreline and 100 metres further out (Infomar 2016 ), a shallow water long wave would be travelling at between 14-31.3 m/s, which coincides with the average speed of an atmospheric disturbance of between 16–42 m/s (Linares et al. 2016 ). This suggests that a meteotsunami event occurring off the northwest coast of Ireland would likely be amplified by Proudman resonance in this instance. 5. Conclusion In this study, we considered several hypotheses to explain the videoed phenomenon: A strong storm surge event A strong astronomical tide A seismically or volcanically triggered tsunami A meteotsunami Neither the location of Storm Franklin’s eye or the subsequent wind speed strength from it at 08:50 UTC on the 21st matched up with the expected conditions of a strong storm surge event. A high tide was present at 08:50 UTC on the 21st, however without the influence of a new or full moon, or at perigee, it was not of the magnitude that would cause the type of event seen in the video. Two magnitude 6 or over earthquakes occurred on the 21st, however neither was located in a region that could generated a tsunami that would affect Ireland. No volcanic activity capable of creating a tsunami occurred on the 21st . The investigation concludes that the phenomenon recorded at Portsalon Golf Course represents a meteotsunami, driven by rapid atmospheric pressure changes and jet stream influence. The presence, partial absence, and then presence again of a strong jet stream over Ireland appeared to manipulate atmospheric pressure conditions, subsequently aiding the formation of sea-level oscillations. Using the time period of the videoed event, partnered with hourly atmospheric pressure rates, specific sea-level anomalies, and the presence of the jet stream, it was suggested that the videoed event was not an isolated event. The majority of observations, conditions and results found during this investigation strongly align with other studies that investigated similar events. The literature indicates that meteotsunami events are far more common than previously expected, and their intensity and frequency are only likely to increase with the effects of climate change. Increasing the general public’s awareness and understanding of complex hazards such as meteotsunamis is important to mitigate the potential hazard of these events. Declarations Funding GM was supported by the ObsSea4Clim project that is funded by the European Union, Horizon Europe Funding Programme for Research and Innovation under grant agreement number: 101136548. ObsSea4Clim contribution nr. XX, the A4 project (Grant-Aid Agreement No. PBA/CC/18/01) which is carried out with the support of the Marine Institute under the Marine Research Programme funded by the Irish Government, and the Research Ireland centre iCRAG under grant number 13/RC2077_P2. Competing Interests The authors have no relevant financial or non-financial interests to disclose. Author Contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Lionel D Swan and Gerard D McCarthy. The first draft of the manuscript was written by Lionel D Swan and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. References Chanson (2009) Current knowledge in hydraulic jumps and related phenomena. A survey of experimental results. https://doi.org/10.1016/j.euromechflu.2008.06.004 Giles D, McConnell B, and Dias F (2020) Modelling with Volna-OP2—Towards Tsunami Threat Reduction for the Irish Coastline. Geosciences 2020, 10 (6), 226; https://doi.org/10.3390/geosciences10060226 Infomar (2016) Infomar Programme, Mulroy Bay & Lough Swilly Bathymetric contour chart 1:100,000. https://secure.dccae.gov.ie/GSI_DOWNLOAD/Marine/Data/INFOMAR_Charts/Mulroy_Swilly/INF16_MU_SW_BY_100_R01.pdf Kearns D (2020) Tsunamis pose significant hazard to the south eastern and western coasts of Ireland, new study suggests. Lead by Professor Frederic Dias, UCD School of Mathematics and Statistics. https://www.ucd.ie/newsandopinion/news/2020/june/26/tsunamisposesignificanthazardtothesoutheasterna ndwesterncoastsofirelandnewstudysuggests/ Kim M, Woo S, Eom H, et al (2022) Towards observation- and atmospheric model-based early warning systems for meteotsunami mitigation: A case study of Korea. Weather and Climate Extremes, 37.https://doi.org/10.1016/j.wace.2022.100463 Lewis C, Smyth T, Williams D, et al (2023) Meteotsunami in the United Kingdom: the hidden hazard. Natural Hazards and Earth System Sciences, 23, 2531-2546. https://nhess.copernicus.org/articles/23/2531/2023/ Linares A, Bechle AJ and Wu C.H (2016) Characterization and assessment of the meteotsunami hazard in northern Lake Michigan. Journal of Geophysical research: Oceans, 121(9), 7141-7158. https://doi.org/10.1002/2016JC011979 Martinius and Gowland (2010) Tide-influenced fluvial bedforms and tidal bore deposits (Late Jurassic Lourinhã Formation, Lusitanian Basin, Western Portugal). https://doi.org/10.1111/j.1365-3091.2010.01185.x Marine Institute (2022a) Tidal Observations. https://www.marine.ie/site-area/data-services/real-time-observations/tidal-observations-0 Marine Institute (2022b) The Irish Marine Data Buoy Observation Network. https://www.marine.ie/site-area/data-services/real-time-observations/irish-marine-data-buoy-observation-network McCarthy GD and Berry A (2022) Observation of a meteotsunami on the south coast of Ireland. Weather, 77(8), 281-282. https://doi.org/10.1002/wea.4273 Mendes-Victor L, Oliveira CS, Pais I et al (1994) Earthquake Damage Scenarios in Lisbon for Disaster Preparedness. In: Tucker, B.E., Erdik, M., Hwang, C.N. (eds) Issues in Urban Earthquake Risk. NATO ASI Series, vol 271. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-8338-1_18 Met Eireann (2024) 1 minute High Frequency Wind Speed and Atmospheric Pressure Data across several Weather Stations along the West Coast, Ireland. Met Eireann (2023) Annual Climate Statement for 2022. https://www.met.ie/annual-climate-statement-for-2022#:~:text=Overall%2C%202022's%20average%20shaded%20air,2007%20the%20previous%20warm est%20year.&text=All%20available%20sunshine%20totals%20were,%2DTerm%20Average%20(LTA). Met Eireann (2022) Climate Statement for winter 2021/2021 and February 2022. https://www.met.ie/climate-statement-for-february-2022#:~:text=A%20strong%20stratospheric%20polar%20vortex,in%20the%20Atlantic%20further%20south. NOAA (2023a) What is a meteotsunami? National Ocean service. https://oceanservice.noaa.gov/facts/meteotsunami.html NOAA (2023b) What is storm surge? National Ocean Service. https://oceanservice.noaa.gov/facts/stormsurge-stormtide.html NWS (2015) What is a Meteotsunami? National Tsunami Hazard mitigation Program. https://nws.weather.gov/nthmp/meteotsunamis.html Olbert AI and Hartnett M (2010) Storms and surges in Irish coastal waters. Ocean Modelling, 34(1-2), 50-62. https://doi.org/10.1016/j.ocemod.2010.04.004 OPW (2025) HYDRO-DATA. https://waterlevel.ie/hydro-data/#/overview/Waterlevel?period=P7D Rabinovich AB (2020) Twenty-Seven years of Progress in the Science of Meeteorological Tsunamis Following the 1992 Daytona Beach Event. Pure and Applied Geophysics, 177, 1193-1230. https://link.springer.com/article/10.1007/s00024-019-02349-3 Renzi E, Bergin C, Kokina T et al (2023) Meteotsunamis and other anomalous “tidal surge” events in Western Europe in summer 2022. Physics of Fluids, 35.https://doi.org/10.1063/5.0139220 Shields J (2022) A rather unusual storm surge this morning @PortsalonGolf links. https://twitter.com/johnnyshields1/status/1495717053713592324 Sibley A (2022) Meteotsunami reported around Britain and Ireland, and northern France, 18-19 June 2022. Weather, 77(8), 279-280. https://doi.org/10.1002/wea.4271 Smithsonian Institution (n.d.) Sangeang Api, Global Volcanism Program. https://volcano.si.edu/volcano.cfm?vn=264050 Tappin DR (2017) Tsunamis from submarine landslides. Geology Today, 33(5), 190-200. https://doi.org/10.1111/gto.12200 Vilibic I and Sepic J (2017) Global mapping of nonseismic sea level oscillations at tsunami timescales. Scientific Reports, 7. https://www.nature.com/articles/srep40818 Villalonga J, Amores A, Monserrat S et al (2023) Observational study of the heterogeneous global meteotsunami generated after the Hunga Tonga–Hunga Ha’apai Volcano eruption. Sci Rep 13, 8649 (2023). https://doi.org/10.1038/s41598-023-35800-6 Williams DA, Schultz DM, Horsburgh KJ et al (2021) An 8-yr Meteotsunami Climatology across Northwest Europe: 2010-17. Journal of Physical Oceanography, 51(4), 1145-1161. https://doi.org/10.1175/JPO-D-20-0175.1 Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 11 Jul, 2025 Reviewers invited by journal 10 Jul, 2025 Editor assigned by journal 01 Jul, 2025 First submitted to journal 01 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7020306","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":483713726,"identity":"45abc773-5906-4784-948c-d0595b93a037","order_by":0,"name":"Lionel David Swan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFUlEQVRIie2PsWrDMBCGLwiU5dqsMgnNK5wJFR0MfhWHgruYkil49OQuhayBvESmrFUJpItLt+LgJdDVQ8YMhla2M7QQee6gbzh0hz7uPwCL5R9CrK6zc3ckDwft/A54p0Jt01vG4chJmokwK78qMMy2HqnmLczB+mx3OBL49Pau4CplOPnMbtenmYDrfmIIxh/cJcF0nT0G4KQcZRHJ/XMdDJVBQTlEgkCqiMBNsVFyrBURmJVKB5Mfpd6VCpys9JaqVsYHs6LP721yvUVlhDSMZNFuMZzPeOjo5NOXvKTXJA5QFOG8GJFAjpeD+YvtTpxiz3cWkftV0bc/WN1v9mXl3YyfLp9/ps3w5wt2/bdYLBZLNz+TME74d9Uv7wAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0009-0005-7492-9669","institution":"Maynooth University","correspondingAuthor":true,"prefix":"","firstName":"Lionel","middleName":"David","lastName":"Swan","suffix":""},{"id":483713727,"identity":"e1880d03-2d0d-40e1-a662-223fa97d6d52","order_by":1,"name":"Gerard D McCarthy","email":"","orcid":"","institution":"Maynooth University","correspondingAuthor":false,"prefix":"","firstName":"Gerard","middleName":"D","lastName":"McCarthy","suffix":""}],"badges":[],"createdAt":"2025-07-01 12:26:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7020306/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7020306/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86666847,"identity":"b802a0e0-52a3-47bf-97da-644402d6cc97","added_by":"auto","created_at":"2025-07-14 11:10:22","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1738314,"visible":true,"origin":"","legend":"\u003cp\u003eStill framed images showing the ‘unusual storm surge’ conditions during the videoed event recorded at Portsalon golf club, county Donegal on the 21st February 2022 at 08:50 UTC \u003cstrong\u003eSource \u003c/strong\u003eShields J (2022)\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/72ee693e071be7c3e9837ba2.png"},{"id":86668107,"identity":"0e2d1f7a-b48a-470e-b3d6-a0eb2f156dd8","added_by":"auto","created_at":"2025-07-14 11:18:22","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":201884,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of (purple filled diamonds) tide gauge stations, (dark red filled circles) weather stations, including met buoy M4, (green filled diamond) the Portsalon Golf Club where the video was recorded. Numbers associated with weather stations indicate the lag in minutes of the passing of the atmospheric wave (direction indicated by arrow) identified in this analysis\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/c33179fc14888a705659d911.png"},{"id":86666860,"identity":"dfda4dbe-23f9-4bb9-bc08-a77cce5ee3ed","added_by":"auto","created_at":"2025-07-14 11:10:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":149570,"visible":true,"origin":"","legend":"\u003cp\u003eTidal data from the Letterkenny \u0026amp; Malin Head tidal stations between the 19th and 22nd of February 2022. The blue (green) line shows the observed water level at Letterkenny (Malin Head), the orange (yellow) line shows the predicted tide at Letterkenny (Malin Head), the pink (black) line shows non-tidal anomalies at Letterkenny (Malin Head). The black dotted line shows the timing of the videoed event\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/3d7c3db044160281e7cd5c94.png"},{"id":86666853,"identity":"159a78e0-fb51-485d-918f-e76167c4017f","added_by":"auto","created_at":"2025-07-14 11:10:22","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":160398,"visible":true,"origin":"","legend":"\u003cp\u003eNon-tidal sea-level anomalies recorded at 6 tidal stations between the 19\u003csup\u003eth\u003c/sup\u003e and 22\u003csup\u003end\u003c/sup\u003e of February 2022. The pink line shows water level from Newmills river station located up stream from Letterkenny. The black dotted line shows the timing of the videoed event\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/119b40c09d5ad6f0f9d01fbe.png"},{"id":86666854,"identity":"f7e1f676-1044-42c4-96b1-972d62fe31b2","added_by":"auto","created_at":"2025-07-14 11:10:23","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":91167,"visible":true,"origin":"","legend":"\u003cp\u003eAtmospheric pressure recorded at 5 weather stations between the 19th and 22nd of February 2022. Black dotted line represents the timing of the videoed event\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/855e75d57aaeb9994b8f5444.png"},{"id":86666849,"identity":"094ee8bb-4421-475b-8dd5-fe81ab3cdb01","added_by":"auto","created_at":"2025-07-14 11:10:22","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":151485,"visible":true,"origin":"","legend":"\u003cp\u003eWind speed recorded across 4 weather stations located along the western coast of Ireland between the 19\u003csup\u003eth\u003c/sup\u003e and 22\u003csup\u003end\u003c/sup\u003e of February 2022. Black dotted line represents the timing of the videoed event\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/eac01ef0fdfaab9b9904cff6.png"},{"id":86670984,"identity":"43e1b052-2b6b-4ff3-b015-eadd016846c2","added_by":"auto","created_at":"2025-07-14 11:34:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3521875,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7020306/v1/a39efdc0-c4ef-4b6f-bad4-32ad1ff99410.pdf"}],"financialInterests":"","formattedTitle":"Investigating a Suspected meteotsunami along the Northwest Coast of Ireland in February 2022","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAt 08:50 UTC on the 21st of February 2022, a video was captured and posted on Twitter (now X.com) titled \u0026ldquo;A rather unusual storm surge this morning\u0026rdquo; (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The recording of such phenomena in recent years has raised public awareness of unusual sea-level related events in Ireland (McCarthy and Berry \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) and has increased the consciousness of the associated hazard. The video shows a propagating wave travelling inland from a sea inlet and flooding the Golf Course of Portsalon next to Lough Swilly, Co Donegal, Ireland. The phenomenon resembled that of a meteotsunami or other extreme disturbance such as a tidal bore or extreme seiche.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMeteotsunamis typically result from rapid atmospheric pressure shifts, often linked to storms, fast-moving weather systems, or winds (NOAA \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2023a\u003c/span\u003e; Vilibic and Šepic 2017). In February 2022, in the week preceding the video, Ireland was struck by three named storms: Storm Dudley on the 16th, Storm Eunice on the 18th, and Storm Franklin on the 20th (Met Eireann 2023). This was attributed to the presence of a highly active North Atlantic jet stream flowing towards Ireland during that period (Met Eireann \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eStorms can generate ocean waves that travel at a similar speed to a pressure wave resulting in Proudman resonance and the formation of a meteotsunami (NWS \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). As they reach the coast, meteotsunamis alter water levels similar to seismic tsunamis, causing rapid drops followed by sudden rises (Lewis et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Both share a high frequency of 2 minutes to 2 hours (Kim et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Most meteotsunamis go unnoticed or are misclassified, especially in winter during unsettled weather (NOAA \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2023a\u003c/span\u003e). However, stronger events can cause severe flooding and fatalities, influenced by pressure disturbance magnitude, shelf depth, and coastline shape (Renzi et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The occurrence of meteotsunami events in Irish waters is common and these events tend to be some of the largest meteotsunamis experienced across north-western Europe (Williams et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). One such event occurred on the 18th June 2022 and was observed across the whole of the south coast of Ireland and southern Wales (McCarthy and Berry \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Sibley \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Public awareness of this was high due to filming of the unusual event, which stood out due to otherwise calm conditions.\u003c/p\u003e\u003cp\u003eA meteotsunami is not the only possible explanation for the videoed event. The event occurred on the approach to high tide, which is unusual for meteotsunamis but is the most common time for tidal bores. Tidal bores are wave phenomena that form due to the unbalancing of the hydrodynamic system. They require a large tidal range, and their development relies on the convergence and/or divergence of the major tidal constituents and is further amplified by other factors such as ocean basin geometry (Chanson \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). The combination of independent conditions like the occurrence of large tides and low river discharge has been associated with tidal bores (Martinius and Gowland \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Tidal bores are famous in certain locations, such as on the Severn Estuary; however, they are not well known on Lough Swilly.\u003c/p\u003e\u003cp\u003eDue to the proximity of several named storms, there is a potential that this was a storm surge event. Storm surges are defined as the anomalous escalation in seawater level during a storm. Storm surges are calculated as the height of the water level exceeding the astronomical tide (NOAA \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023b\u003c/span\u003e). Storm surges in Irish waters are typically greater along the west coast compared to the east coast due the prevailing origin of Atlantic Storms from the west and the open geography of the west in comparison to the more sheltered Irish Sea (Olbert and Hartnett \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). They typically occur on longer timescales than meteotsunamis and tidal bores and are not usually associated with wave-like phenomena. However, there is the possibility that storm Franklin triggered extreme seiching in Lough Swilly or a freak wave.\u003c/p\u003e\u003cp\u003eSeismic tsunamis are infrequent in Irish waters but do remain in popular consciousness. The last major tsunami to hit Irish waters and affect the island of Ireland was the 1755 Lisbon tsunami, which was generated by a massive earthquake of magnitude 8.5\u0026ndash;9 (Mendes-Victor et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1994\u003c/span\u003e). This tsunami hit the coast of Ireland and saw the creation of an island out of Aughinish, south of Galway Bay, and severely damaged Galway\u0026rsquo;s Spanish Arch located within Galway Harbour (Giles et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Kearns \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Tsunamis can also be formed by the occurrence of a volcanic eruption. The Hunga-Tonga Volcanic eruption that occurred in January 2022 sent powerful atmospheric and oceanic disturbances around the globe which caused both tsunamis and meteotsunamis (Villalonga et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Submarine landsides have also been known to cause tsunamis in the past. In 1998, Papua New Guinea was devastated by a 15-metre-high tsunami which was attributed to a sudden shift in the seabed off the northern coastline (Tappin \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThis study contextualises and describes the event that featured in the video from the 21st February 2022, collates available meteorological and sea-level observations to describe the wider context and assesses whether this extreme event is likely due to meteotsunami, tidal bore, or other disturbance.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Sea-Level Data\u003c/h2\u003e\u003cp\u003eTidal data was collected from two separate sources, the OPW\u0026rsquo;s HYDRO-DATA interactive map (OPW \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) and from the Marine Institute\u0026rsquo;s Real Time Tidal Observations (Marine Institute \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2022a\u003c/span\u003e). In total six tidal stations: Malin Head, Letterkenny, Aranmore Island, Killybegs, Enniscrone and Ballyglass (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), located along the northwest coast of Ireland provided 5-minute high frequency data that was used in this analysis. All stations are fully tidal, except for Letterkenny, which is heavily fluvial, being situated at the head of Lough Swilly on the River Swilly. To avoid the possibility of false tidal readings, the Newmills water level station located further upstream was analysed and the results were compared to the Letterkenny tidal data. Tidal harmonics were fitted to the fully tidal stations over timeperiods of at least 1 year, using the \u003cem\u003eTideHarmonics\u003c/em\u003e package in R, fitting at least 64 tidal constituents to ensure goodness of fit.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Wind Speed and Pressure\u003c/h2\u003e\u003cp\u003eAtmospheric data from weather stations were provided by Met Eireann (Met Eireann 2024) and gathered from the Marine Institute\u0026rsquo;s Marine Data Buoy Observation Network (Marine Institute \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2022b\u003c/span\u003e). The 1-minute high frequency Met Eireann data provided wind speed data and atmospheric pressure data from 00:00:00 on the 19th February 2022 to 23:59:00 on the 22nd February 2022 at Mace Head (not shown), Markree Castle, Malin Head, Finner, and Belmullet (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). This was joined with the Marine Institute\u0026rsquo;s ocean buoy wind speed measured from the M4 station.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Seismic and Volcanic Data\u003c/h2\u003e\u003cp\u003eEarthquake observations from the USGS Earthquake Hazards program and reports of volcanic activity from the Smithsonian Institution\u0026rsquo;s Global Volcanism Program provided insight into whether the videoed event could have been seismic in nature. On the 21st of February 2022, only two magnitude 6 or higher earthquakes occurred around the globe. The first occurred in the Southern Ocean off the coast of the Balleny Islands, Antarctica. The second occurred in the northwestern tip of Argentina. Volcanic activity was reported on the 21st of February 2022. Sangeang Api volcano in Indonesia began to release ash plumes on the 17th and continued until the 22nd (Smithsonian Institution n.d.). Due to the remoteness of these events, a seismic tsunami was ruled out and no further analysis was conducted on this hypothesis.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Sea-level fluctuations in Lough Swilly\u003c/h2\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the evolution of sea-level in Lough Swilly at Letterkenny (head of the sea lough) and Malin Head (mouth of the sea lough) over the 19th to the 22nd of February. \u003cem\u003eStorm\u003c/em\u003e Franklin\u0026rsquo;s path crossed the north Atlantic as it moved between the south coast of Iceland and the north coast of Ireland before tracking southeast over Scotland and approaching the Netherlands. The lowest pressure recorded within the eye of Storm Franklin was 952 hPa at 9am on the 20th of February when the storm was located directly off the south coast of Iceland. The closest the storm\u0026rsquo;s eye got to Ireland occurred between 9pm on the 20th and 3am on the 21st, with a pressure of between 963 hPa and 974 hPa. By the time the videoed event was recorded, the remains of storm Franklin\u0026rsquo;s eye were located closer to the Netherlands than Ireland. At this time, mean sea-level pressure at risen to 983 hPa.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eHeavy rainfall was associated with the Storm Franklin, which raised river levels in the River Swilly resulting in a notable fluvial event on the 20th where, at low tide, levels at Letterkenny rose to nearly 2 m above expected levels (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, \u003cb\u003epink\u003c/b\u003e). Winds rose across the northwest of Ireland as the storm transited, with a notable increase in non-tidal variability evident at Malin Head from mid-morning on the 20th. A positive storm surge developed with the passing of Storm Franklin, peaking close to low tide on the morning of the 21st. This positive surge rapidly reversed following the passage of Storm Franklin, with non-tidal water levels dropping by approximately 1 m between successive low tides on the 21st .\u003c/p\u003e\u003cp\u003eAt the time of the event at 08:50 UTC, the tide was nearly at its maximum. This tidal magnitude was not extreme or unusually high and did not occur in conduction with a spring tide. Compared to the 20th and 19th, the tidal range was decreasing ahead of the occurrence of a neap tide on the 23rd. The event does not stand out in comparison to previous days where larger non-tidal anomalies were experienced.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.2. Non-tidal sea-level fluctuations\u003c/h2\u003e\u003cp\u003eHigh levels of non-tidal sea-level fluctuations were observed across tidal stations in the northwest of Ireland. The rapid and unpredictable shifts in non-tidal sea-level began to occur just before 12pm on the 20th and did not appear to fully subside until the end of the 21st in most stations (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The maximum sea-level anomalies recorded were 0.818 m at Killybegs (20th, 6:15 UTC), 0.743 m at Aranmore Island (21st, 00:25 UTC), 1.005 m at Enniscrone (21st, 06:10 UTC), 1.507 m at Malin Head (21st, 03:35 UTC), and 0.415 m at Ballyglass (21st, 02:05 UTC). Significant shifts in the 40-minute rolling standard deviation also begin to appear before 12:00 UTC on the 20th across all the stations and does not appear to fully return to normal levels in most stations by the 22nd. At the time of the event, non-tidal levels were falling.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.3. Atmospheric Conditions\u003c/h2\u003e\u003cp\u003eAtmospheric pressure data across 5 weather stations recorded a pressure increase of between 26.6\u0026ndash;28.4 hPa over the 24-hour period between 12:00 UTC on the 20th and 12:00 UTC on the 21st. The first 12 hours saw a pressure rate increase of between 0.191 hPa/h and 0.975 hPa/h. The second 12-hour period saw a dramatic increase in the rate of atmospheric increase of between 1.24 hPa/h and 2.15 hPa/h. The two weather stations furthest north, Finner and Malin Head had the lowest pressure increase per hour during the first 12 hours, but had the highest pressure increase per hour during the second 12 hours (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMace Head, a coastal weather station south of the area pictured in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, experienced an increase in pressure that exceeded 1005 hPa in the early hours of the 21\u003csup\u003est\u003c/sup\u003e. 40 minutes later, the Belmullet station exceed 1005 hPa. Several hours later, the pressure wave arrived at Markree Castle, followed shortly after by Finner and then lastly the 1005 hPa threshold was exceeded at Malin Head (furthest north) just minutes after the videoed event occurred. This same period was when atmospheric pressure was increasing at its highest rate (2.4 hPa/h) at Malin Head. The rate of pressure increase from the M4 buoy was very similar to that of the onshore weather stations. In the first 12 hours, pressure rate increase was 0.575 hPa/h, and in the second 12 hours it followed the significant positive trend set by the onshore stations, measuring 1.791 hPa/h.\u003c/p\u003e\u003cp\u003eAcross several weather stations located along the western coast of Ireland, wind speeds of over 60 kph were recorded towards the end of the 20th and in the early hours of the 21st of February 2022 (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The highest wind speed recorded at the \u0026lsquo;M4\u0026rsquo; buoy was just over 35 kph in the early hours of the 21st. At the time of the videoed event, wind speeds observed at the closest weather station to Portsalon golf club, the Malin Head weather station, had dropped to around 40 kph.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eBased on the videographic evidence from Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea significant water level event occurred on the morning of the 21st February at Portsalon golf club. Besides the original video, no other evidence of \u0026lsquo;unusual\u0026rsquo; sea-level activity was reported. Based on our analysis here, the conditions on the morning of the 21st of February were not unusual in comparison to those since the arrival of Storm Franklin. Similar events may well have occurred but not have been recorded.\u003c/p\u003e\u003cp\u003eBased on the tracking of Storm Franklin\u0026rsquo;s eye, the north and west of Ireland was the location of a storm surge event between 9:00 UTC on the 20th and 03:00 UTC on the 21st, during which Storm Franklin was the closest to the Irish landmass. However, at 09:00 UTC on the 21st, the remains of Storm Franklin\u0026rsquo;s eye was closer to the Netherlands than it was to Ireland, non-tidal sea-levels were falling, and the most severe weather conditions associated with the storm were past at Portsalon Golf Club. Wind speed data supported this observation, with peak speeds recorded across stations from 9:00 UTC on 20th February to 03:00 UTC on 21st February. A relatively significant drop off in wind speed occurred after this time, with a wind speed of 40 kph recorded at the Malin Head weather station around 09:00 UTC on the 21st, which is the average for that time of year. This suggests a storm surge event would be unlikely the driver of the filmed event.\u003c/p\u003e\u003cp\u003eA high tide did coincide with the timing of the videoed event. However, the tides magnitude was not classified as extreme or unusually high and did not occur in conduction with a spring tide. Compared to the 20th and 19th, the tidal range was decreasing ahead of the occurrence of a neap tide on the 23rd. The moon was not especially close to the earth on the 21st, which suggests the videoed event was not a result of the perigee or any astronomical tide anomaly.\u003c/p\u003e\u003cp\u003eTidal data from the Letterkenny tidal station showed very large non-tidal fluctuations on February 20th. At low tide, a sudden increase in water level was observed. However, this occurred well over a day before the videoed event was recorded. The analysis of water level data from a further upstream river station, Newmills, showed what appeared to be a rapid and significant influx of water into the river system prior to the increase observed in Letterkenny. Associated with the arrival of Storm Franklin, a heavy precipitation event occurred, causing the influx of water into the river system and influencing the tidal data of the Letterkenny station. However, this had abated by the time of the event on the 21st and was therefore not likely linked.\u003c/p\u003e\u003cp\u003eObservation from Letterkenny tidal station provides possible evidence that the filmed phenomenon could have been an unusual seiching event during high tide. Low-pass filtered data (10 minute) from Malin Head may also present signs of seiching at high tide, however it is difficult to discern. Buncrana tidal station, also located in Lough Swilly, was not active at the time of the event, but, since its installation in November 2024, has not observed a comparable signal of high tide seiching. As no in-situ tidal station exists at Portsalon, or indeed at any location on the western shore of Lough Swilly, confirmation of a seiching event is difficult.\u003c/p\u003e\u003cp\u003eTidal data across other stations across the northwest of Ireland showed very similar water level anomalies beginning to occur before 12:00 UTC on the 20th. The anomalies are first seen in Malin Head and propagate further south reaching Ballyglass last. The Malin Head station did see the greatest single anomaly, however it occurred after all but one of the other stations observed their maximum anomalies. A possible reason for this is the shape of the coastline directly affecting the intensify of the sea-level anomaly at each station \u003cb\u003e(\u003c/b\u003eRabinovich \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eA secondary propagation was also hypothesised, one based off the timing of the videoed event. This propagation suggested that there was an almost 180-degree shift in the direction of the triggering factor, occurring in the early hours of the 21st. Using this propagation, Ballyglass receives the first sea-level anomalies followed by Enniscrone, Aranmore and then Malin Head. Based off this timeline, further analysis into whether the videoed event could be observed across the other stations, and what magnitude the sea-level anomalies were conducted.\u003c/p\u003e\u003cp\u003eResults from the analysis of the atmospheric pressure data also suggests a change occurred during the early hours of the 21st. The rate of atmospheric pressure increase before 00:00 UTC on the 21st was relatively low across all the stations, ranging from 0.191 hPa/h to 0.975 hPa/h. However, after 00:00 UTC on the 21st, rates of atmospheric pressure increase rose dramatically, ranging from 1.24 hPa/h to 2.15 hPa/h. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e depicts this slow increase of pressure across the northwest of Ireland before the occurrence of a sudden and rapid shift in the rate of atmospheric pressure increase.\u003c/p\u003e\u003cp\u003eUsing the south to north propagation derived from the videoed event\u0026rsquo;s timeframe, sea-level anomalies and atmospheric pressure increases over one-hour periods were linked. The Belmullet weather station measured an increase of 2 hPa from 03:00 to 04:00 UTC on the 21st. This timeframe matched the period in which Ballyglass tidal station observed a sea-level anomaly of 0.389 metres. The Malin Head weather station measured an increase of 2.4 hPa from 08:50 to 09:50 UTC on the 21st. This timeframe matched the period in which Malin Head tidal station observed a sea-level anomaly of 0.501 metres. Based on these results, it appears that a significant atmospheric pressure increase might have caused these sea-level anomalies, and this suggests the videoed event could have been a meteotsunami. Similar rates of pressure change were observed during the 18th June 2022 meteotsunami event that affected the south coast of Ireland (McCarthy and Berry \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eA possible explanation as to what caused the observed shift in propagation and sudden increase in atmospheric pressure rates after 00:00 UTC on the 21st exists within the strength and positioning of the jet stream over Ireland. As the tidal data began to show unusual oscillations just before 12:00 UTC on the 20th, the jet stream had been moving towards Ireland, influencing the northwest first before covering the rest of Ireland by 12:00 UTC. This would coincide with the slight north to south propagation experienced within the sea-level anomalies before 00:00 UTC on the 21st. Between 12:00 UTC on the 20th and 00:00 UTC on the 21st, the jet stream gradually moved towards the south, resulting in the northwest coast falling outside its influence. After 00:00 UTC on the 21st, the jet stream\u0026rsquo;s fastest winds began to move back across the country from the southwest to the northeast. This second propagation coincides with the occurrence of the videoed event and the rapid increase in atmospheric pressure from south to north. These observations suggest the jet stream had a significant role in the creation and distribution of atmospheric pressure conditions that were suitable for the formation of sea-level oscillations linked to meteotsunami events. During the June 18th southern Ireland meteotsunami event, the jet stream was only present over the affected area of the south coast, highlighting its role in producing meteotsunami events (Renzi et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eProudman resonance is the typical mechanism to amplify the magnitude of meteotsunamis. Considering the depth of the continental shelf off the coast of Donegal is between 20\u0026ndash;40 metres closest to the shoreline and 100 metres further out (Infomar \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), a shallow water long wave would be travelling at between 14-31.3 m/s, which coincides with the average speed of an atmospheric disturbance of between 16\u0026ndash;42 m/s (Linares et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). This suggests that a meteotsunami event occurring off the northwest coast of Ireland would likely be amplified by Proudman resonance in this instance.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eIn this study, we considered several hypotheses to explain the videoed phenomenon:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eA strong storm surge event\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eA strong astronomical tide\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eA seismically or volcanically triggered tsunami\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eA meteotsunami\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eNeither the location of Storm Franklin\u0026rsquo;s eye or the subsequent wind speed strength from it at 08:50 UTC on the 21st matched up with the expected conditions of a strong storm surge event. A high tide was present at 08:50 UTC on the 21st, however without the influence of a new or full moon, or at perigee, it was not of the magnitude that would cause the type of event seen in the video. Two magnitude 6 or over earthquakes occurred on the 21st, however neither was located in a region that could generated a tsunami that would affect Ireland. No volcanic activity capable of creating a tsunami occurred on the 21st .\u003c/p\u003e\u003cp\u003eThe investigation concludes that the phenomenon recorded at Portsalon Golf Course represents a meteotsunami, driven by rapid atmospheric pressure changes and jet stream influence. The presence, partial absence, and then presence again of a strong jet stream over Ireland appeared to manipulate atmospheric pressure conditions, subsequently aiding the formation of sea-level oscillations. Using the time period of the videoed event, partnered with hourly atmospheric pressure rates, specific sea-level anomalies, and the presence of the jet stream, it was suggested that the videoed event was not an isolated event. The majority of observations, conditions and results found during this investigation strongly align with other studies that investigated similar events. The literature indicates that meteotsunami events are far more common than previously expected, and their intensity and frequency are only likely to increase with the effects of climate change. Increasing the general public\u0026rsquo;s awareness and understanding of complex hazards such as meteotsunamis is important to mitigate the potential hazard of these events.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGM was supported by the ObsSea4Clim project that is funded by the European Union, Horizon Europe Funding Programme for Research and Innovation under grant agreement number: 101136548. ObsSea4Clim contribution nr. XX, the A4 project (Grant-Aid Agreement No. \u0026nbsp;PBA/CC/18/01) which is carried out with the support of the Marine Institute under the Marine Research Programme funded by the Irish Government, and the Research Ireland centre iCRAG under grant number 13/RC2077_P2.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Lionel D Swan and Gerard D McCarthy. The first draft of the manuscript was written by Lionel D Swan and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eChanson (2009) Current knowledge in hydraulic jumps and related phenomena. A survey of experimental results. https://doi.org/10.1016/j.euromechflu.2008.06.004 \u003c/li\u003e\n \u003cli\u003eGiles D, McConnell B, and Dias F (2020) Modelling with Volna-OP2—Towards Tsunami Threat Reduction for the Irish Coastline. \u003cem\u003eGeosciences\u003c/em\u003e 2020, \u003cem\u003e10\u003c/em\u003e(6), 226; https://doi.org/10.3390/geosciences10060226 \u003c/li\u003e\n \u003cli\u003eInfomar (2016) Infomar Programme, Mulroy Bay \u0026amp; Lough Swilly Bathymetric contour chart 1:100,000. https://secure.dccae.gov.ie/GSI_DOWNLOAD/Marine/Data/INFOMAR_Charts/Mulroy_Swilly/INF16_MU_SW_BY_100_R01.pdf\u003c/li\u003e\n \u003cli\u003eKearns D (2020) Tsunamis pose significant hazard to the south eastern and western coasts of Ireland, new study suggests. Lead by Professor Frederic Dias, UCD School of Mathematics and Statistics. https://www.ucd.ie/newsandopinion/news/2020/june/26/tsunamisposesignificanthazardtothesoutheasterna\nndwesterncoastsofirelandnewstudysuggests/ \u003c/li\u003e\n \u003cli\u003eKim M, Woo S, Eom H, et al (2022) Towards observation- and atmospheric model-based early warning systems for meteotsunami mitigation: A case study of Korea. Weather and Climate Extremes, 37.https://doi.org/10.1016/j.wace.2022.100463\u003c/li\u003e\n \u003cli\u003eLewis C, Smyth T, Williams D, et al (2023) Meteotsunami in the United Kingdom: the hidden hazard. Natural Hazards and Earth System Sciences, 23, 2531-2546. https://nhess.copernicus.org/articles/23/2531/2023/\u003c/li\u003e\n \u003cli\u003eLinares A, Bechle AJ and Wu C.H (2016) Characterization and assessment of the meteotsunami hazard in northern Lake Michigan. Journal of Geophysical research: Oceans, 121(9), 7141-7158. https://doi.org/10.1002/2016JC011979 \u003c/li\u003e\n \u003cli\u003eMartinius and Gowland (2010) Tide-influenced fluvial bedforms and tidal bore deposits (Late Jurassic Lourinhã Formation, Lusitanian Basin, Western Portugal). https://doi.org/10.1111/j.1365-3091.2010.01185.x \u003c/li\u003e\n \u003cli\u003eMarine Institute (2022a) Tidal Observations. https://www.marine.ie/site-area/data-services/real-time-observations/tidal-observations-0 \u003c/li\u003e\n \u003cli\u003eMarine Institute (2022b) The Irish Marine Data Buoy Observation Network. https://www.marine.ie/site-area/data-services/real-time-observations/irish-marine-data-buoy-observation-network \u003c/li\u003e\n \u003cli\u003eMcCarthy GD and Berry A (2022) Observation of a meteotsunami on the south coast of Ireland. Weather, 77(8), 281-282. https://doi.org/10.1002/wea.4273 \u003c/li\u003e\n \u003cli\u003eMendes-Victor L, Oliveira CS, Pais I et al (1994) Earthquake Damage Scenarios in Lisbon for Disaster Preparedness. In: Tucker, B.E., Erdik, M., Hwang, C.N. (eds) Issues in Urban Earthquake Risk. NATO ASI Series, vol 271. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-8338-1_18 \u003c/li\u003e\n \u003cli\u003eMet Eireann (2024) 1 minute High Frequency Wind Speed and Atmospheric Pressure Data across several Weather Stations along the West Coast, Ireland.\u003c/li\u003e\n \u003cli\u003eMet Eireann (2023) Annual Climate Statement for 2022. https://www.met.ie/annual-climate-statement-for-2022#:~:text=Overall%2C%202022's%20average%20shaded%20air,2007%20the%20previous%20warm\nest%20year.\u0026amp;text=All%20available%20sunshine%20totals%20were,%2DTerm%20Average%20(LTA). \u003c/li\u003e\n \u003cli\u003eMet Eireann (2022) Climate Statement for winter 2021/2021 and February 2022. https://www.met.ie/climate-statement-for-february-2022#:~:text=A%20strong%20stratospheric%20polar%20vortex,in%20the%20Atlantic%20further%20south. \u003c/li\u003e\n \u003cli\u003eNOAA (2023a) What is a meteotsunami? National Ocean service. https://oceanservice.noaa.gov/facts/meteotsunami.html\u003c/li\u003e\n \u003cli\u003eNOAA (2023b) What is storm surge? National Ocean Service. https://oceanservice.noaa.gov/facts/stormsurge-stormtide.html\u003c/li\u003e\n \u003cli\u003eNWS (2015) What is a Meteotsunami? National Tsunami Hazard mitigation Program. https://nws.weather.gov/nthmp/meteotsunamis.html \u003c/li\u003e\n \u003cli\u003eOlbert AI and Hartnett M (2010) Storms and surges in Irish coastal waters. Ocean Modelling, 34(1-2), 50-62. https://doi.org/10.1016/j.ocemod.2010.04.004\u003c/li\u003e\n \u003cli\u003eOPW (2025) HYDRO-DATA. https://waterlevel.ie/hydro-data/#/overview/Waterlevel?period=P7D \u003c/li\u003e\n \u003cli\u003eRabinovich AB (2020) Twenty-Seven years of Progress in the Science of Meeteorological Tsunamis Following the 1992 Daytona Beach Event. Pure and Applied Geophysics, 177, 1193-1230. https://link.springer.com/article/10.1007/s00024-019-02349-3\u003c/li\u003e\n \u003cli\u003eRenzi E, Bergin C, Kokina T et al (2023) Meteotsunamis and other anomalous “tidal surge” events in Western Europe in summer 2022. Physics of Fluids, 35.https://doi.org/10.1063/5.0139220\u003c/li\u003e\n \u003cli\u003eShields J (2022) A rather unusual storm surge this morning @PortsalonGolf links. https://twitter.com/johnnyshields1/status/1495717053713592324 \u003c/li\u003e\n \u003cli\u003eSibley A (2022) Meteotsunami reported around Britain and Ireland, and northern France, 18-19 June 2022. Weather, 77(8), 279-280. https://doi.org/10.1002/wea.4271\u003c/li\u003e\n \u003cli\u003eSmithsonian Institution (n.d.) Sangeang Api, Global Volcanism Program. https://volcano.si.edu/volcano.cfm?vn=264050\u003c/li\u003e\n \u003cli\u003eTappin DR (2017) Tsunamis from submarine landslides. Geology Today, 33(5), 190-200. https://doi.org/10.1111/gto.12200 \u003c/li\u003e\n \u003cli\u003eVilibic I and Sepic J (2017) Global mapping of nonseismic sea level oscillations at tsunami timescales. Scientific Reports, 7. https://www.nature.com/articles/srep40818\u003c/li\u003e\n \u003cli\u003eVillalonga J, Amores A, Monserrat S et al (2023) Observational study of the heterogeneous global meteotsunami generated after the Hunga Tonga–Hunga Ha’apai Volcano eruption. \u003cem\u003eSci Rep\u003c/em\u003e 13, 8649 (2023). https://doi.org/10.1038/s41598-023-35800-6 \u003c/li\u003e\n \u003cli\u003eWilliams DA, Schultz DM, Horsburgh KJ et al (2021) An 8-yr Meteotsunami Climatology across Northwest Europe: 2010-17. Journal of Physical Oceanography, 51(4), 1145-1161. https://doi.org/10.1175/JPO-D-20-0175.1\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"natural-hazards","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nhaz","sideBox":"Learn more about [Natural Hazards](https://www.springer.com/journal/11069)","snPcode":"11069","submissionUrl":"https://submission.nature.com/new-submission/11069/3","title":"Natural Hazards","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"meteotsunami, sea-level anomalies, atmospheric pressure, jet stream, Lough Swilly, Ireland","lastPublishedDoi":"10.21203/rs.3.rs-7020306/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7020306/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eOn 21\u003csup\u003est\u003c/sup\u003e February 2022 at 08:50 UTC, an unusual sea-level event was captured on video at Portsalon Golf Club, Lough Swilly, Co Donegal, Ireland. This phenomenon resembled that of a meteotsunami, an atmospherically driven sea-level anomaly. This study provides context surrounding the origin and classification of the event via the use of high-frequency tidal data, atmospheric pressure data, and wind speed records from nearby tidal and weather stations. A rapid shift in atmospheric pressure following Storm Franklin, and the occurrence of a high tide matched the timing of the event. However, neither the tidal nor the wind conditions were extreme at this time suggesting the event was not a strong astronomical tide or storm surge. The absence of seismic and volcanic activity inferred it was not a traditional tsunami. The aligned timing of the video, the sudden increase in atmospheric pressure rate, the movement of the jet stream over Ireland, and the sea-level anomalies point to a meteotsunami. Improvements in public awareness and monitoring are crucial to our understanding of these events, and to our ability to mitigate the risks associated, especially under our changing climate.\u003c/p\u003e","manuscriptTitle":"Investigating a Suspected meteotsunami along the Northwest Coast of Ireland in February 2022","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-14 11:10:18","doi":"10.21203/rs.3.rs-7020306/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-07-11T08:23:50+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-10T21:40:53+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-02T02:54:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"Natural Hazards","date":"2025-07-01T08:25:26+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"natural-hazards","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nhaz","sideBox":"Learn more about [Natural Hazards](https://www.springer.com/journal/11069)","snPcode":"11069","submissionUrl":"https://submission.nature.com/new-submission/11069/3","title":"Natural Hazards","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a273caac-9621-420e-8f05-edf802b1375a","owner":[],"postedDate":"July 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-07-14T11:10:18+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-14 11:10:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7020306","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7020306","identity":"rs-7020306","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}