Southampton, UK: Researchers at the University of Southampton have conducted the most comprehensive spatial analysis to date of storm surges along the UK and Ireland’s coastlines. The findings, published in the June edition of the journal Weather and Climate Extremes, reveal significant regional variations in the intensity and duration of storm surges, with the north of the Irish Sea experiencing the longest and largest surges, while the southwest coast of England sees the shortest and smallest surges.
Over a period spanning four decades, the winter seasons of 1989/90 and 2013/14 emerged as the periods with the highest number and most severe storm surge events. These findings were derived from data collected between 1980 and 2017, highlighting 270 extreme storm surge events based on their duration, footprint size, severity, and frequency.
Understanding Storm Surges
A storm surge is an abnormal rise in seawater level during a storm, exceeding the normal tide height for the area. This phenomenon is caused by wind pushing water onshore and is influenced by a storm’s size, speed, and trajectory. The storm surge footprint represents the extent of simultaneous flooding along a stretch of coastline and is crucial for understanding the potential damage associated with coastal flooding.
“Storm surges are the most important driver of flooding in many coastal areas,” explains Ivan Haigh, a Professor at the University of Southampton and co-author of the study. “Our research will help improve the accuracy of statistical models used to predict the impact of storm surges on different localities, allowing for better countermeasures and adaptation to increasing risks with climate change.”
Key Findings
- Regional Variations: The north of the Irish Sea experienced the most extensive and prolonged storm surges, while the southwest coast of England had the shortest and smallest surges.
- Most Severe Events: The most extreme surge event was during the winter of 1989/90, particularly a storm on 26 February 1990, which caused significant flooding in Towyn and Clwyd in Wales, leading to the evacuation of five thousand people.
- Stormiest Season: The winter of 2013/14 was identified as the stormiest season within the study period, featuring 13 severe flooding events. One notable surge on 5 December 2013 resulted in 36 flood warnings in East Anglia and the loss of properties along the coasts of Norfolk, Suffolk, and Essex.
Implications for Future Flood Risk Management
Lead author Dr. Paula Camus of the University of Southampton and Universidad de Cantabria (Spain) emphasized the importance of learning from past storm surges to inform future coastal flood risk responses. “Changes to our climate will likely mean more frequent and extreme events, so having accurate data on which to base decisions about infrastructure and emergency response is crucial. We hope our study can better inform the assessment of risk and impacts.”
Methodology and Future Research
The research involved scientists from Spain, the USA, and The Netherlands and identified eight distinct surge footprint types linked to the characteristics of the storms that caused them. While the study did not account for astronomical influences on tide heights, the researchers plan to incorporate this factor in future analyses.
The methodology developed can also be adapted and applied to any coastal region globally, offering a valuable tool for understanding and mitigating coastal flood risks worldwide.
This study underscores the critical need for detailed and region-specific analysis of storm surges to better predict and manage the impacts of coastal flooding in the context of climate change.
Reference: https://www.southampton.ac.uk/news/2024/06/coastal-flooding.page