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Hurricanes


Hurricanes are large, severe storms that come inland from the ocean. These spiraling terrors are masses of water, wind, lightning, and thunder. It can stretch over 600 miles wide, with winds up to 200 miles per hour. Hurricanes spin counter-clockwise and usually last about a week. The center of a hurricane is called the eye. The eye is the calmest part. Hurricanes usually develop over tropical oceans, with a temperature above 81 degrees Fahrenheit. The heat of the water is the main energy source for hurricanes. They will weaken once they get on land or the temperature lowers. These can drop 2.4 trillion gallons of rain a day. Hurricanes usually only occur in tropical waters since they fuel on the warm temperatures.

Development of Hurricanes


Hurricanes have three stages: tropical depressions, tropical storms, and finally a hurricane. The first stage is a tropical depression. Tropical depressions are when lowered pressure and slight rotation first appear. Once a tropical depression has sustained winds of 35-64 knots, it becomes a tropical storm. In this stage, they become more organized and have heavy rainfall. Tropical storms become hurricanes when the sustained wind speed has reached at least 64 knots and the pressure continues to drop.

Structure of a Hurricane


The eye of a hurricane is what the rest of the hurricane rotates around. This is usually a couple miles wide and is the calmest part of the storm. Some people even confuse being in the eye of a hurricane, with the storm being over. The Coriolis force keeps the strong winds from getting to the center, forming the "eye". The eye wall, however, is much different from the eye. The eye wall is the part of the storm that directly forms around the eye. The most devastating winds and most intense rainfall occurs here. The Coriolis force and convergence cause the air to be pushed up more violently than any other part of a hurricane. Spiral bands surround the eye wall and form the rest of the hurricane. These contain more rain and wind.

Damages of Hurricanes


Hurricanes can cause storm surges, flooding, and riptides. These are common due to the large amounts of rainfall and strong winds that can last up to two weeks.
A storm surge is when the water level rises from having low air pressure, high winds, and high waves that reach land. Flooding comes from having so much rainfall over a period of time. The severity of the winds causes the most damage, followed by flooding. The winds can create tornadoes along with the hurricane. Hurricanes are put into categories based on the damage it causes.
Saffir-Simpson Hurricane Scale
Category 1: Trees are uprooted and mobile homes are damaged.
Sustained Winds: 64-82 knots
Category 2: Damage to poorly constructed homes, small boats, and piers.
Sustained Winds: 83-95 knots
Category 3: Severe damage to homes, mobile homes may be stripped from the ground, flooding along coasts.
Sustained Winds: 96-113 knots
Category 4: Mobile or manufactured homes are leveled, irreparable damage to overhang structures, major beach erosion, inland flooding.
Sustained Winds: 114-135 knots
Category 5: Utility buildings blown away, roof and structure failure, major flooding.
Sustained Winds: 136 and above knots

Sources


http://ww2010.atmos.uiuc.edu
http://www.infoplease.com/ce6/weather/A0858709.html
http://en.wikipedia.org/wiki/Saffir-Simpson_Hurricane_Scale
http://environment.nationalgeographic.com/environment/natural-disasters/hurricane-profile.html