A hurricane is a type of storm called a tropical cyclone. Hurricanes form over tropical or subtropical waters. A tropical cyclone is a low-pressure weather system that has organized thunderstorms but no fronts. A front is a boundary separating two air masses of different densities. A storm becomes a hurricane when its maximum sustained winds reach 74 miles per hour.
The Saffir-Simpson Wind Scale rates hurricanes on a one to five scale, depending on their maximum wind speeds. The ratings are an attempt to predict the amount of property damage that can be expected. Hurricanes reaching category three are considered major.
- category 1
- 74-95 MPH
- 96-110 MPH
- 111-129 MPH
- category 4
- 130-156 MPH
- category 5
- 157 MPH or higher
Hurricanes primarily originate in the Atlantic Ocean, Caribbean Sea, or the Gulf of Mexico.
A six-year rotating list of names is updated and maintained by the World Meteorological Organization. The current system of naming Atlantic tropical storms began in 1953. Initially, only female names were used. In 1979, male names were added to the lists. Since then, female and male names alternate. This is why Harvey was followed by Irma. Since there are six rotating lists, the 2017 list will be used again in 2023. When a storm does so much damage that reusing the name would be insensitive, the name is replaced. At a minimum, Harvey and Irma will be replaced before this list is used again in 2023.
Hurricane, cyclone, and typhoon refer to the same kind of storm. The different names are used depending on where the storm is located. Hurricane is used for storms in the Atlantic and Northeast Pacific. Cyclone is used for storms in the South Pacific and the Indian Ocean. Typhoons occur in the Northwest Pacific.