Storm surge is a particularly damaging phenomenon caused by a combination of strong onshore winds and low atmospheric pressure. This results in abnormal volumes of water accumulating against the coastline, manifesting as a raised sea level which can last for several hours. Storm surges are major drivers of coastal flooding. They should not be confused with large ocean swells, which may look impressive when they crash against the coastline, but do not necessarily cause flooding!

These data are produced in-house by the SAWS storm surge forecasting system. A regional, depth-averaged ocean model has been employed, with a 1 minute computational time step. SAWS forecasters use this tool to consult regularly with Disaster Risk Management to ensure sufficient forewarning for storm surge events. The map provides a regional overview, whilst the time series plots below provide detail for specific areas of interest. The Marine Unit constantly monitors the performance of the wave model using observed data.