August 26, 2011
With all the talk on the news about preparation for Hurricane Irene, a lot of you may be wondering what makes hurricanes such a big deal. Hurricanes are the world’s worst storms. That is surprising to some people, since tornadoes have much stronger winds that sometimes get as high as 300 miles (483 km) per hour. Hurricane winds rarely blow at even half that speed - in fact, a tropical storm becomes a hurricane when winds exceed just 74 miles (119 km) per hour.
So why are hurricanes (called "typhoons" in the North Pacific and "cyclones" in the Indian Ocean) the world’s deadliest storms?
A tornado is usually less than a mile (1.6km) wide on the ground, and lasts for less than an hour. So while a tornado causes a great deal of destruction, only a limited area is affected. A hurricane affects a much, much larger area. Even a small hurricane is hundreds of miles wide, and it can last for days or even weeks. In a single day, a large hurricane releases energy that is equal to two hundred times the amount of electricity generated on the entire planet. These are powerful storms!
Hurricane Irene is a particularly large and dangerous storm - nearly 600 miles (1000 km) wide at the time this photograph was taken by NASA’s Terra satellite. You can see bands of thunderstorms spiraling tightly around a dense center. That is the circular shape of a well-developed hurricane.
The most important thing, when a hurricane is approaching, is to be prepared. If you are in an area that is subject to coastal flooding, you must heed the warnings of local government officials and evacuate when they tell you to. If you are not in a flood zone, there are many things you should do to prepare for not only the storm itself, but also for at least three days without electricity and water. FEMA (the Federal Emergency Management Agency) has a good checklist on their website.
To get the latest local information about the approaching storm, go to any Internet search engine, and type in "[your county] [your state] emergency management." That will give you a link for the Office of Emergency Management for your area, where you will find up-to-date information and phone numbers to help you get information about how the storm will affect your area.
We have learned a lot about hurricanes in recent years, and as our weather forecasting software, warning systems and emergency planning get better, we are saving lives. The more we learn about hurricanes, the better our chances of staying safe.
I updated my book HURRICANES in 2007, after Hurricane Katrina devastated New Orleans, becoming the costlest and most destructive hurricane in U.S. history. You can learn more about the science behind hurricanes, and see many incredible photographs of these powerful forces of nature.
Posted by: Seymour Simon
