It would be hard not to know about the devastating hurricanes that have hit coastal cities along the Gulf of Mexico, Atlantic Coast and Caribbean islands during the past few hurricane seasons. Several of the hurricanes have caused catastrophic damage not only to the coastal cities and towns, but inland communities as well. 

It may surprise you to know that very few of the storm over warm water develop into hurricanes.There are many factors that need to be present in the environment before a full-fledged hurricane forms. Many of the storms that form over Earth's warm water oceans break apart before they ever develop into events classified as tropical depressions.

Read the explanation below of how hurricanes form. Remember as you read, that if environmental conditions are not met along the way, a hurricane will not form.

The Formation of a Hurricane

---

To begin the formation of a hurricane, several thunderstorms over warm water oceans come together begin to rotate around essential core. The core is an area of low air pressure. The organize storm is now called a tropical depression.

Several atmospheric factors must be present for the tropical storm to increase in intensity. Hurricane specialist record many features but generally emphasize several factors that are quite unique to tropical storm Hurricane formation.

The rotation is caused by the Coriolis effect. The Coriolis effect makes moving objects appear to curve toward the right in the northern hemisphere awards the left in the southern hemisphere due to the earths rotation. When is an ocean currents are affected buy Earth's rotation. Hurricane cloud winds rotate counterclockwise in the northern hemisphere and clockwise in the Southern Hemisphere.

If atmospheric conditions allow the storms winds to increase to 39 mph, the storm is classified as a tropical storm.

• The storm must be developing over warm water. The water must be at least 80°F. The warm water provides the energy for increased evaporation of water from the ocean surface.
• The warm water must be deep enough to increase the energy available. Warm temperature decreases with depth; the deep of the water, the lower the temperature. This is even true in warm tropical waters. But, during the summer months, the water slowly heats from the surface down. Eventually, deeper waters may be warm enough to provide the energy needed to increase the storms intensity. The ocean water must be warm enough to a depth of at least 200 feet.
• There should be very little wind shear in the area. Wind shear occurs when there is a difference in wind speed and direction over a short distance. Strong wind shear can not stop the formation of hurricane walls.
• A rapid cooling of air temperature with height allows for condensation to occur and quick development of more cloud formation in the storm wall.

If all these factors are present the storm intensifies.

Air continues to rise in the low-pressure area of the storm.

Clouds continue to form as more and more water evaporates from the surface.

A wall of clouds form around the corner and the war continues to rotate (due to the Coriolis Effect)

Winds increase. When the winds are over 74 mph, the store is classified as a hurricane (also called a tropical cyclone)

Even when a hurricane moves over land and loses some strength it can still retain enough force to cause severe property damage, detrimental storm surges, and loss of life.

The hurricane is pushed along a path by winds outside the organized storm and is affected by weather fronts that may have formed large distances away. As long as the hurricane stays over warm water it will increase in strength. If it moves over cooler water or heads inland, it loses its source of energy and the hurricane will begin to decrease in strength.  When a hurricane moves into the middle latitudes, it is is considered to be "extratropical" (outside tropical areas). Eventually the storm breaks apart when the energy needed to maintain the eye wall is gone.

Although the storm may no longer be classified as a hurricane, tropical storm, or even a tropical depression, it can't still be quiet deadly. Hurricanes produce high winds and torrential rains. Storm surges pound over coasts, flood vast areas and cause devastating property damage. It can take years for communities to completely recover from such a severe weather event.

 

 

Check Your Understanding

---

1. Name 3 conditions that must be present for a hurricane to formAnd explain why each condition is needed.

 

 

 

 

2. Why does a hurricane lose strength when it moves over land?

 

 

 

 

3. How can a hurricane that moves over land still be so destructive?