What is Storm Surge and Why Is It Dangerous

U.S.|Storm surge from hurricanes tin endanger lives and harm property.

• Aug. 21, 2021, 4:13 p.m. ET

Hurricanes are defined by their almighty winds. But the tempest surges they nutrient tin often beryllium conscionable arsenic destructive successful coastal communities.

Henri, which strengthened into a hurricane connected Saturday greeting with winds of 75 miles per hour, was expected to make dangerous tempest surges successful parts of Long Island, Connecticut, Massachusetts and Rhode Island.

Storm surge is defined arsenic an abnormal emergence successful the water level generated by a storm, implicit and supra the predicted astronomical tide. The surges are produced by water h2o moving inland, pushed by the unit of the wind.

In the unfastened ocean, hurricanes tin lb the h2o without producing a surge. But adjacent the coast, the shallower h2o is blown inland, threatening spot and lives.

The deepest h2o volition hap on the contiguous seashore successful areas of onshore winds, wherever the surge volition beryllium accompanied by ample and unsafe waves, the National Hurricane Center said.

Surge-related flooding depends connected the timing of the surge and the tidal cycle, and tin alteration greatly implicit abbreviated distances, the halfway said.

In 2008, Ike, a Category 2 hurricane that made landfall adjacent Galveston Island successful Texas, produced surges of 15 to 20 feet supra mean tide levels, the halfway said. Property harm was estimated astatine $24.9 billion.

Henri, a Category 1 storm, was expected to nutrient a tempest surge of up to 5 feet, meaning the h2o could scope 5 feet supra the mean predicted astronomical tide.

The National Hurricane Center said that areas that are placed nether a tempest surge informing are astatine hazard of “life-threatening inundation.” People successful those areas should heed immoderate evacuation instructions from section officials, the halfway said.