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Answer Sheet
Posted at 03:25 PM ET, 08/26/2011

Understanding hurricanes: Facts and resources

With Hurricane Irene on a collision course with the United States, this is a good time to read up on how hurricanes form, move and have been resistant to human efforts to tame the most destructive storms on Earth.

Here are some facts and resources that you can share with your kids about these monster storms, which are known by different names depending upon where you are: In the United States they are called hurricanes; in the Pacific, typhoons and cyclones and hurricanes; in Australia, willy-willies.

Growing up in Miami, and then living there again as an adult, I experienced a number of them, and once took a reporting trip in a hurricane hunter plane that went in and out of a storm for 13 hours.

What still amazes me is what scientists don’t yet know about the dynamics of hurricanes to help make forecasting more predictable.

Here’s some of what we do know:

What: Hurricanes are powerful storm systems that produce torrential rain and intense winds. They form over warm ocean water.

According to NASA:

Tropical cyclones are like giant engines that use warm, moist air as fuel. That is why they form only over warm ocean waters near the equator. The warm, moist air over the ocean rises upward from near the surface. Because this air moves up and away from the surface, there is less air left near the surface. Another way to say the same thing is that the warm air rises, causing an area of lower air pressure below. Air from surrounding areas with higher air pressure pushes in to the low pressure area. Then that “new” air becomes warm and moist and rises, too. As the warm air continues to rise, the surrounding air swirls in to take its place. As the warmed, moist air rises and cools off, the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface.”

Strength:Tropical storms are classified as hurricanes when they have maximum sustained winds of at least 74 mph.

Category 1: 74-95 mph

Category 2: 95-110 mph

Category 3: 111-130 mph

Category 4: 131-155 mph

Category 5: 156 mph and above

Where: According to the International Hurricane Research Center at Florida International University in Miami, the 10 areas of the U.S. mainland that are most vulnerable to hurricanes are:

1. New Orleans, La.

2. Lake Okeechobee, Fla.

3. Florida Keys

4. Coastal Mississippi

5. Miami/Ft. Lauderdale, Fla.

6. Galveston/Houston, Tex.

7. Cape Hatteras, N.C.

8. Eastern Long Island, N.Y.

9. Wilmington, N.C.

10. Tampa/St. Petersburg, Fla.

Taming hurricanes: Humans have not mastered a method to lessen the impact of a hurricane, but it hasn’t been for a lack of trying. In the 1960s, scientists began experimenting with seeding clouds in hurricanes with silver iodide, which would supposedly cause supercooled water in the storm to freeze and reduce the power of the winds. It didn’t work as well as hoped, and Project Stormfury was abandoned.

Resources

The National Geographic has a lot of information here that is accessible to kids as well as adults.

Here’s how hurricanes get their names, and lists of hurricanes by year.

And you can find more at this Web site, a joint effort of the NOAA Research and the College of Education at the University of South Alabama.

Specifically for children is a Web site by FEMA, here .

And for those interested in every little detail about hurricanes, and Irene in particular, go to this Web site of the National Hurricane Center.

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By  |  03:25 PM ET, 08/26/2011

 
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