Most of the facts about hurricanes that we know come from studying historical data and taking measurements of the storms when they occur. We know where hurricanes originate and we can figure out where they're likely to go and how powerful they'll be. Yet we still don't entirely understand how they work or what causes them. Here are some things that you should know about hurricanes.
A hurricane is a very severe tropical storm, organized around a central "eye" of rotating wind. To be classified as a hurricane, wind speeds must be at least 75 MPH. If the winds are slower, it is just a tropical storm.
A hurricane can be up to 600 miles across and have wind speeds as high as 200 MPH. Because of the low atmospheric pressure in the eye of a hurricane, water rises up into the eye and causes a storm surgs when the hurricane hits land. The combination of water and wind can raise ocean levels by several feet when a hurricane makes landfall, flooding coastal areas.
Hurricanes can be measured on the Saffir-Simpson Scale, which measures both wind speed and storm surge. The National Weather Service used this scale experimentally for the first time in 2009, although questions remain about its ability to predict storm surge damage. On the Saffir-Simpson Scale, a Class 1 hurricane has a wind speed of 75 to 95 MPH and does minimal damage. A Class 5 hurricane has winds over 155 MPH and is considered a catastrophic hurricane.
The Atlantic hurricane season begins June 1 and ends November 30. The peak Atlantic hurricane months are from August through October.
Meteorologists give names to hurricanes. The names are reused from year to year, unless the storm is particularly destructive. Katrina was retired as a hurricane name following the massive damage it inflicted in Louisiana and Mississippi in 2005. Up until 1979, all hurricane names were women's names. In 1979, men's names were added to the list.
Hurricanes gather energy from warm ocean water. The warm water serves to fuel the hurricane. Hurricanes dissipate over land and weaken when they move from warm tropical waters into the cooler waters of the northern Atlantic.
Hurricanes occur in the Southern Atlantic Ocean, the Eastern Pacific Ocean, the Caribbean Sea and the Gulf of Mexico. Most hurricanes form in a band between 5 and 15 degrees north and south of the equator. Pacific hurricanes are also called typhoons. The Eastern Pacific hurricane season is from May 15 to November 30.
A hurricane rotates counter-clockwise around its eye. The Coriolis Force is responsible for this spin. The eye of the hurricane is the center of the storm, and it is the calmest part of the storm. The eye has light winds and fair weather. If the eye passes over you during a hurricane, you might see blue skies outside and think the storm is over. In reality, the eye wall is closing in with some of the storm's strongest winds and rain. You should never go outside during a hurricane, especially if the sky suddenly clears.
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