It’s no secret that tropical storms and hurricanes produce damaging winds and unleash heavy rains that can lead to fatal flooding. But what might be less obvious is that the storm surges they produce can be equally destructive and are often the greatest threat to life and property along coasts.
A storm surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides, according to the National Hurricane Center. It is caused when the force of the winds moving cyclonically around the storm pushes water is pushed toward the shore.
The height of a storm surge is dependent on a storm’s size, forward motion and angle of approach, as well as the depth of the coastline, said Dennis Feltgen, a meteorologist and spokesman for the National Hurricane Center. A change in a storm’s track, even of just 20 miles, can make a difference, he said, and every mile of coastline along the Eastern United States and the Gulf of Mexico is susceptible to storm surge from tropical cyclones.
“Storm surge has historically been the primary cause of death arising from tropical cyclones,” with approximately 50 percent of all direct fatalities, Mr. Feltgen said.
In 2017, the National Weather Service and the National Hurricane Center began issuing storm surge watches and warnings along the East Coast and the Gulf Coast, and, in 2019, to Puerto Rico and the U.S. Virgin Islands. Since 2017, 21 tropical cyclones — including 14 hurricanes, five of which were major — have made landfall and prompted storm surge watches or warnings, he said.
In 2021, Hurricane Ida roared into Louisiana as a Category 4 storm, producing dangerously high storm surges and testing the city’s system for resisting catastrophic flooding. Some areas along the coast experienced a storm surge as high as 14 feet, according to a report from the center. It is estimated that Ida’s winds and storm surge caused about $55 billion of damage in Louisiana.
In 2008, Ike, a Category 2 hurricane that made landfall near Galveston Island in Texas, produced surges up to 20 feet above normal tide levels. Property damage was estimated to be $24.9 billion. And, before that, Hurricane Katrina in 2005 produced a storm surge 25 to 28 feet above normal tide levels and caused about $75 billion in damage in the New Orleans area and along the Mississippi coast.
