The hurricanes' worst killer comes from the sea, in the form storm surge, which claims nine of ten victims in a hurricane.

It is a large dome of water often 50 to 100 miles wide that sweeps across the coastline near where a hurricane makes landfall. The surge of high waters topped by waves is devastating. The stronger the hurricane and the shallower the offshore water, the higher the surge will be. Along the immediate coast, storm surge is the greatest threat to life and property. If the storm surge arrives at the same time as the high tide, the water height will be even greater. The storm tide is the combination of the storm surge and the normal astronomical tide.

As the storm crosses the continental shelf and moves close to the coast, mean water level may increase 15 feet or more. The advancing storm surge combines with the normal astronomical tide to create the hurricane storm tide. This buildup of water level can cause severe flooding in coastal areas, particularly when the storm surge coincides with normal tides. Because much of the United States' densely populated coastline along the Atlantic and gulf coasts lies less than 10 feet above mean sea level, the danger from storm sure is great.

Wave and current action associated with the surge also causes extensive damage. Water weighs some 1,700 pounds per cubic yard; extended pounding by frequent waves can demolish any structures not specifically designed to withstand such force.

Currents set up along the coast by the gradient in storm surge heights and wind combine with waves to severely erode beaches and coastal highways. Many buildings withstand hurricane winds until their foundations, undermined by erosion, are weakened and fail. Storm tides, waves, and currents in confined harbors severely damage ships, marinas, and pleasure boats. In estuarine and bayou areas, intrusions of salt water endanger the public health and create bizarre effects, like salt-crazed snakes fleeing Louisiana's flooded bayous.

Storm Tide Facts
1. Over 6,000 people were killed in the Galveston Hurricane of 1900 - mostly by the storm tide.
2. Hurricane Camille in 1969 produced a 25-foot storm tide in Mississippi.
3. Hurricane Hugo in 1989 generated a 20-foot storm tide in South Carolina.