A storm surge is the unusual rise in sea level usually associated with hurricanes and tropical storms prior to and during landfall. Storm surges are caused primarily by high winds pushing on the ocean surface. This causes the water to pile up higher than the ordinary sea level. Tropical cyclone-induced storm tides can increase the mean water level 5 meters or more. As these winds pass over the surface of the sea they generate waves, which flood the shoreline. The rise in water level and the hammering effect of the waves can cause coastal erosion, flooding, scour roads, undercut sea walls and demolish buildings. Storm Surge is responsible for much of the damage caused by severe weather systems, especially in large, low-lying coastal settlements. According to the US National Weather Service National Hurricane Center, the greatest potential for loss of life related to a hurricane is from storm surge.
You are most at risk from a storm surge if you live close to the coast. A storm surge causes damage in two ways:
- The rising water level floods areas that are usually beyond the water line.
- The breaking waves impact higher along the beachfront and as they crash into the shore, they send water rushing even further inland.
Storm impact is expected to worsen in the future due to increased cyclone activity and heightened storm surges. These surges will, in turn, create more damaging flood conditions in low-lying coastal areas.
Video of how Storm Surge occurs