What are tropical depressions, tropical storms and hurricanes?
• A Tropical Depression is the beginning stages of a tropical cyclone with maximum sustained winds less than 39 mph. • A Tropical Storm is an organized system of thunderstorms that forms over tropical waters with a defined circulation and maximum sustained winds of 39 to 73 mph (34-63 knots). • A Hurricane has many of the same characteristics of a tropical storm but is more intense with maximum sustained winds of 74 mph (64 knots) or higher. In the western Pacific, hurricanes are called typhoons and similar storms in the Indian Ocean are called cyclones. • Hurricanes are further classified according to the Saffir-Simpson Scale. • Category 1 (Minimal Damage): Pressure greater than 28.94 inches, Winds 74-95 mph, Storm surge 4-5 feet • Category 2 (Moderate Damage): Pressure 28.50-28.91 inches, Winds 96-110 mph, Storm surge 6-8 feet • Category 3 (Extensive Damage): Pressure 27.91-28.47″, Winds 111-130 mph, Storm surge 9-12 feet • Category 4 (Extreme Damage): Pressure 27.17-27.88″, Winds 13
