Hurricanes and Their Distructive Forces

A hurricane is a cyclone (low pressure system) developing in the tropics with a minimum wind speed of 74 miles per hour. The wind rotates in counterclockwise direction around the center of the storm, called the "eye", where the winds are nearly calm. The wind in an intense hurricane may exceed 150 mph with gusts above 200 mph just outside of the storm's center. Hurricane force winds may extend out 100 miles from the center with gale force winds (39 mph or higher) extending outward 250 miles. Bands of very intense thunderstorms spiral outward from the eye of the hurricane for several hundred miles producing torrential rain, and occasionally spawning tornadoes when they begin moving over land.

WIND
Hurricane force winds, in some cases gusting to nearly 200 mph, can cause widespread and significant damage to many buildings. Wind gusts to nearly 150 mph destroyed many houses in South Dade County, Florida, when Hurricane Andrew moved onshore in August of 1992. Hurricane force winds can also create a deadly barrage from roofing material, metal siding, and outdoor furniture. Hurricane winds can also be damaging well inland, as evidenced in 1988, when wind gusts of 100 mph were recorded in Charlotte, N.C., as Hurricane Hugo moved inland. These strong winds toppled many trees, which fell into houses and disrupted electrical services. The rules for seeking safety from the hurricane's destructive winds are similar to those for tornado safety. These include moving to a small interior room on the lowest floor of a well- constructed house or building, which is safe from storm surge flooding.

RAINFALL
Rainfall totals of 10 inches or more are not uncommon when a tropical storm or hurricane moves ashore. These heavy rains can complicate drainage problems in areas experiencing storm surge flooding. If rainfall amounts of this magnitude occur over north or central Louisiana, destructive flash flooding and river flooding can occur. In 1989, Tropical Storm Allison produced 15 to 25 inches of rain over central and northwest Louisiana causing widespread flooding. This resulted in 3 deaths and 250 million dollars in property damage. In June of 1986, rainfall from the remnants of Hurricane Bonnie caused extensive flash flooding in northwest Louisiana. Over 380 homes and 20 businesses suffered damage in Shreveport.