Department of Emergency Management and Security
What It Is
Hurricanes and tropical storms are violent weather systems with well-defined surface circulation. Threats from hurricanes include high winds, heavy rainfall, storm surge, coastal and inland flooding, rip currents, and tornadoes. Strom storms may be hundreds of miles across, with winds in excess of 150 mph, pushing storm surge floods of a dozen feet or more. Even storms that no longer carry hurricane-force winds may be cause devastating flooding just due to rain (for example, Allison, Irene, Sandy, and Harvey).
Tropical storms rotate in a counter-clockwise direction around the eye. The rotating storm clouds create the "eye-wall," which contains the most destructive winds in the storm. The eastern half of an Atlantic hurricane typically carries the greatest risks in terms of wind and surge.
Hurricanes have winds of 74 mph and up, tropical storms 38-73, and tropical depressions less than 38. The Atlantic hurricane season runs from June 1 to November 30, with the peak occurring between mid-August and late October.