To be classified as a hurricane, a storm must have sustained winds of at least 74 miles per hour. On the Saffir-Simpson hurricane wind scale, a Category 1 hurricane has sustained winds of from 74 to 95 miles per hour.
The wind speeds incurred during a Category 1 hurricane are powerful enough to damage exterior structures on houses and other buildings, fell branches from trees, uproot smaller trees and damage power lines. A Category 2 hurricane has sustained winds of 96 to 110 miles per hour, and the winds of a Category 3 range from 111 to 129 miles per hour. A Category 4 hurricane has winds from 130 to 156 miles per hour, and the most catastrophic hurricane, a Category 5, has winds of 157 miles per hour or greater.