National Hurricane Preparedness Week: Storm Surge

Storm surge is a large dome of water, often 50 to 100 miles wide, that sweeps across the coastline mainly to the right of where a hurricane makes landfall.

Storm surge from Hurricane Hugo in 1989 inundated the South Carolina coast from Charleston to Myrtle Beach. Maximum storm tides, the combination of the actual tide plus the surge of water, reached 20 feet in the area of Cape Romain and Bulls Bay.

The surge of high water, topped by wave action, can be devastating, especially to those along the immediate coast. The stronger the hurricane and the more shallow the coastal shelf, the higher the surge will normally be. In addition, wind driven waves develop on top of the storm tide. This rise in water level can cause severe flooding in coastal areas, particularly if the surge coincides with the occurrence of the high tide.

While the surge poses a severe risk to coastal communities, it also affects rivers, harbors, tributaries and inland lakes. This potentially increases the areas that must be evacuated.

In general, the more intense the storm and the closer a location is to the right front quadrant, the larger the area that must be evacuated.

Wave and current action associated with the tide also causes extensive damage. Water weighs approximately 1700 pounds per cubic yard. Extended pounding by frequent waves can demolish structures not specifically designed to withstand such forces.

The currents created by the tide combine with the action of the waves to severely erode beaches and coastal highways. Many buildings may withstand hurricane force winds until their foundations, undermined by erosion, are weakened and will fail.

Storm Surge Safety Actions

If you decide to leave an area vulnerable to storm surge during a tropical system, minimize the distance you must travel to reach a safe location. Use air travel if possible.

Choose the home of a close friend or relative or a hotel or motel outside the designated evacuation zone.

If neither option is available, consider the closest public shelter outside of the surge zone.

Become familiar with the route you will take before leaving.

Expect traffic congestion and delays during evacuations.

Expect and plan for significantly longer travel times than under normal conditions.