Hurricanes

Hurricanes are severe tropical storms with sustained winds of 74 miles per hour (mph) or greater. Hurricane winds can reach 160 mph and extend inland for hundreds of miles. Hurricanes bring heavy rains and storm surges (dome of ocean water that can be 20 feet at its peak, and 50 to 100 miles wide that crashes into land as the storm approaches). Hurricanes also spawn tornadoes..

Saffir / Simpson Hurricane Scale
Storm size or force is based on what is called the Saffir / Simpson Hurricane Scale. This scale defines five categories of hurricanes as follows:
Category
Sustained Winds (mph)
Storm Surge (feet)
Anticipated Damage
1
74 - 95
4 - 5
Minimal
2
96 - 110
6 - 8
Moderate
3
111 - 130
9 - 12
Extensive
4
131 - 154
13 - 18
Extreme
5
Above 155
Above 18
Catastrophic

Category 1

Damage primarily to shrubbery and trees, foliage, and un-anchored mobile homes. No real damage to other structures, except to poorly constructed signs. Low-lying coastal roads are flooded, piers sustain minor damage, and some small craft in exposed anchorage are torn from their moorings.

Category 2

Considerable damage to shrubbery and tree foliage; some trees are blown down. Major damage to exposed mobile homes. Extensive damage to poorly-constructed signs. Some damage to the roofing material of buildings and some window and door damage. No major damage to buildings.

Coastal roads and low-lying inland escape routes may be cut off by rising water two to four hours before arrival of the hurricane’s center. Piers sustain considerable damage and marinas are flooded. Small craft in unprotected anchorages are torn from their moorings. Evacuation of some shoreline residences and low-lying areas is required.

Category 3

Foliage is torn loose from trees and large trees are blown down. Almost all poorly-constructed signs are blown down. Some damage to the roofing material of buildings, some window and door damage. Small buildings sustain some structural damage and mobile homes are destroyed.

Coastal areas experience serious flooding and many smaller structures near the coast are destroyed. Battering waves and floating debris damages larger structures near the coast. Low-lying inland escape routes are cut off by rising water three to five hours before the hurricane’s center arrives.

Flat terrain, five feet or less above sea level, is flooded inland for eight miles or more. The evacuation of low-lying residences within several blocks of the shoreline is required.

Category 4
Shrubs and trees are blown down. All signs are blown down. Roofing materials, windows, and doors sustain extensive damage. There is complete failure of roofs on many small residences. Mobile homes are completely destroyed. Flat terrain, 10 feet or less above sea level, is flooded inland as far as six miles inland. Major damage to the lower floors of structures near the shore due to flooding and battering by waves or floating debris.

Low-lying inland escape routes are cut off by rising water three to five hours before the hurricane’s center arrives. Major erosion of beaches occurs. Massive evacuation of all residences within 500 yards of the shoreline is required, as well as an evacuation of all single story residences on low ground within two miles of the shore.

Category 5
Shrub and trees are blown down. All signs are blown down. Windows and doors experience very severe or extensive damage. There is a complete failure of roofs on many residences and industrial buildings. There is extensive shattering of glass in windows and doors. Some buildings experience complete failure. Small buildings are overturned or blown away. Mobile homes are completely destroyed.

All structures less than 15 feet above sea level and within 500 yards off shore experience major damage to lower floors. Low-lying inland escape routes are cut off by rising water three to five hours before the hurricane’s center arrives. Massive evacuation of residential areas on low ground within five to 10 miles off shore is required.