Hurricanes and tropical storms are large non-frontal tropical low pressure systems that may or may not have cyclonic surface winds. Should these systems have a maximum sustained surface winds of less than 39 miles per hour are called "tropical depressions." Once the tropical cyclone exceeds wind speeds of 39 miles per hour they are called a "tropical storm" and assigned a name. If winds reach 74 miles per hour they are called a "hurricane."
These storms also bring with them a tidal event known as "storm surge." Storm surge is an off shore rise of water associated with a low pressure weather system and is caused by high winds pushing the ocean's surface causing the water to pile up higher than the ordinary sea level. Most casualties related to a tropical cyclone occur during the storm surge.
Wind Speed (MPH)
74 to 95
5 to 7
To foliage / trees, signs, unanchored mobile homes; minimal damage to other structures; flooding of barrier islands / coastal areas; minor pier damage and small crafts torn from moorings.
96 to 110
7 to 12
Considerable damage to foliage / trees; major damage to mobile homes, building roof, windows, doors; considerable damage to piers, marinas and small crafts; and flooding.
111 to 130
12 to 15
Large trees and signs blown down; some damage to roofing materials, windows, and doors, small buildings; mobile homes destroyed; serious flooding along barrier islands/coast; and large and small structures destroyed by waves / floating debris.
131 to 155
15 to 20
Trees and signs blown down; extensive damage to roofing materials, windows, and doors; complete destruction of mobile homes; major damage to lower floors of structures near the coast/barrier islands due to flooding, waves/floating debris.
20 to 24
Trees blown down; extensive damage to roofs; all signs down; building failures; complete destruction of mobile homes; major damage to lower floors of structures less than 15 feet above sea level in storm surge zones.