Weather : ValleyCentral.com

Hurricane basics

The Atlantic hurricane season begins June 1. Along the Atlantic Coast of the United States, five hurricanes strike in an average three-year period, killing any where from 50 to 100 people and causing billions of dollars in damages. In 2004, more than $40 billion in damages were caused by 15 tropical storms and nine hurricanes. In 2005 along the U.S. Atlantic and Gulf coasts, there were 28 tropical storms, breaking the record of 21 set in 1933; there were 15 hurricanes, with seven of them classified as major. Three of the six hurricanes classified as the strongest ever recorded occurred in 2005: Katrina, Rita and Wilma, with Wilma being identified as the most powerful hurricane ever in the Atlantic Basin.

What is a hurricane?

A hurricane is an intense tropical storm. They can occur in many parts of the world, although often under a different name. For example, the term "hurricane" refers to storms of this type that originate in the Atlantic Ocean. In the Pacific and Indian oceans, these storms can be called either cyclones or typhoons, depending on what region in the Pacific or Indian oceans the storm occurs.

Satellite image of a hurricane over the Atlantic.

Tropical storms can pack powerful winds, but it doesn't get called a hurricane unless the wind speed exceeds 74 mph. Once dubbed a hurricane, the storm is classified using a system called the Saffir-Simpson Hurricane Scale.

Category	Wind speeds mph	Characteristic damage	Examples
Tropical storm	39 to 73	Typical to a severe thunderstorm
Category 1	74 to 95	No real damage to buildings. Damage to unanchored mobile homes. Some damage to poorly constructed signs. Also, some coastal flooding and minor pier damage.	Irene 1999 and Allison 1995
Category 2	96 to 110	Some damage to building roofs, doors and windows. Considerable damage to mobile homes. Flooding damages piers and small craft in unprotected moorings may break their moorings. Some trees blown down.	Bonnie 1998, Georges 1998 and Gloria 1985
Category 3	111 to 130	Some structural damage to small residences and utility buildings. Large trees blown down. Mobile homes and poorly built signs destroyed. Flooding near the coast destroys smaller structure with larger structures damaged by floating debris. Terrain may be flooded well inland.	Keith 2000, Fran 1996, Opal 1995, Alicia 1983 and Betsy 1965
Category 4	131 to 155	More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Terrain may be flooded well inland.	Hugo 1989 and Donna 1960
Category 5	156 and higher	Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Flooding causes major damage to lower floors of all structures near the shoreline. Massive evacuation of residential areas may be required.	Andrew 1992, Camille 1969 and Labor Day 1935.