How destructive storm surge gets depends on both the hurricane and the shape of the land.
Sean Rayford/Getty The St. Johns River rises from storm surge flood waters from Hurricane Irma on Sept.11,2017 in Jacksonville, Florida. Forecasters warned about the potential for dangerous storm surge as Henri strengthened into a hurricane on a path expected to take its eye over or near New York’s Long Island and into New England on August 22, 2021. The storm was expected to reach the coast at full moon, when high tides are higher than normal already. Here’s how Anthony Didlake Jr., a meteorologist at Penn State, recently explained how storm surge forms and why it’s so dangerous. Of all the hazards that hurricanes bring, storm surge is the greatest threat to life and property along the coast. It can sweep homes off their foundations, flood riverside communities miles inland, and break up dunes and levees that normally protect coastal areas against storms. As a hurricane reaches the coast, it pushes a huge volume of ocean water ashore. This is what we call storm surge. This surge appears as a gradual rise in the water level as the storm approaches. Depending on the size and track of the hurricane, storm surge flooding can last for several hours. It then recedes after the storm passes. Water level heights during a hurricane can reach 20 feet or more above normal sea level.
