A tropical storm with winds of 39-73 mph becomes a hurricane when it's winds near the center reach 74 mph. The storm surge is generally 4-5 feet above normal. Damage is mostly to trees and shrubbery, with no real building damage. Average wind speed for a cat. 1 is 74-95mph. Minimum central pressure (980 mb.)

Winds are from 96- 110 mph. Storm surge is generally 6-8 feet above normal. Some roofing material, door and window damage to buildings. Considerable damage to trees and shrubbery with some trees blown down. Considerable damage to signs, mobile homes and poorly constructed piers. Coastal and low lying escape routes may flood 2-4 hours before the arrival of the hurricane's center. Minimum central pressure (80-965 mb.)

This is considered to be a major hurricane. With winds from 111-130 mph. it can generate a storm surge of 9-12 feet above normal. Some structural damage to small residences with a minor amount of curtainwall failures. Damage to trees and shrubbery with leaves and foliage blown off and large trees blown down. Mobile homes and poorly constructed signs are destroyed. Escape routes cut by rising water 3-5 hours before the hurricane' center arrives. Smaller structures at the coast destroyed and larger structures damaged by floating debris. Terrain lower than 5 feet above mean sea level may flood inland 8 miles or more. Evacuation of low lying areas may be required. Minimum central pressure (964-945 mb.)

With winds of 131-155 mph the storm surge runs 13-18 feet above normal. More extensive curtainwall failures with some complete roof structure failures on small residence. All shrubs, signs and trees blown down. COMPLETE DESTRUCTION of mobile homes. Extensive damage to doors and windows. Low lying escape routes maybe cut by rising water 3-5 hours before the arrival of the hurricane's center. Major damage to lower floors of structures near the coast. Terrain lower than 10 feet above mean sea level may be flooded as far inland as 6 miles. Minimum central pressure (944-920 mb) 

Winds greater than 155 mph. Storm surge generally runs greater than 18 feet above normal. Complete roof failure on many residential and industrial buildings. Some complete building failures with small utility buildings blown over or away. All shrubs, trees and signs blown down. COMPLETE DESTRUCTION of mobile homes. Extreme damage to doors and windows. Low-lying escape routes cut by rising water 3-5 hours before the arrival of the hurricane's center. Major damage to all lower floors of all structures located below 15 feet above sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5-10 miles of the coastline maybe required. Minimum central pressure (920 mb or lower)