Tropical Wave: A cluster of clouds and/or thunderstorms without a significant circulation and generally moving from east to west through the tropics.
Tropical Depression: The formative stage of a tropical storm or a hurricane. A tropical depression has a center of circulation and sustained winds of less than 39 mph.
Tropical Storm: The tropical depression has formed and strengthened. This is an organized system of strong thunderstorms with top sustained winds of 39 mph to 73 mph. This is the stage when storms are named.
Category 1: Winds 74-95 mph. Storm surge 4-6 ft above normal. Damage primarily to unanchored mobile homes, shrubbery and trees. Coastal road flooding and minor pier damage.
Category 2: Winds 96-110 mph. Storm surge 6-10 ft above normal. Some roof, door and window damage of buildings. Considerable damage to shrubbery and trees with some trees blown down. Considerable damage to mobile homes and piers. Coastal and low-lying escape routes flood 2-4 hrs before arrival of hurricane center. Small craft in unprotected anchorages break moorings.
Category 3: Winds 111-130 mph. Storm surge 10-16 ft above normal Some structural damage to small residences with a minor amount of curtain wall failures. Damage to shrubbery and trees with foliage blown off trees and large trees blown down. Mobile homes are destroyed. Low-lying escape routes are cut by rising water 3-5 hours before arrival of hurricane center. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 10 ft above sea level may be flooded inland 10 miles or more. Evacuation of low-lying residences along the shoreline may be required.
Category 4: Winds 131-155 mph. Storm surge 16 to 22 ft above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs and trees blown down. Complete destruction of mobile homes. Extensive damage to to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before the arrival of the hurricane center. Major damage to the lower floors of structures near the shore. Terrain lower than 15 ft above sea level may be flooded requiring evacuation of residential areas as far inland as 10 miles.
Category 5: Winds greater than 155 mph. Storm surge greater than 22 ft above normal. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown away. All shrubs, trees and signs blown down, Complete destruction of mobile homes. Severe and extensive window and and door damage. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the hurricane center. Major damage to lower floors of all structures located less than 20 ft above sea level and within 11000 yards of the shoreline, Evacuation of residential areas on low ground within 15 miles of the shoreline may be required.