From space, they appear as a giant mass of swirling clouds that can cover half of the continental United States, but this hides the chaos below. Hurricanes are intensely powerful storms that can flood cities with heavy rains and high surf or wreck them with their strong winds and multiple tornadoes. These storms form slowly over the course of days, as a single storm of heavy rains and strong winds circling a central low-pressure system, known as the “eye.”

Though the center of the hurricane, the eye is calm as the storm rages around it. For decades, the behavior and direction of hurricanes was thought to be unpredictable, but research flights by meteorologists, satellite tracking, and Doppler radar images can now help forecasters pinpoint the strength and direction of hurricanes, giving coastal areas time to save lives.

The facts on hurricanes:

1. A hurricane has to reach sustained winds of at least 74 miles per hour, or 119 kilometers per hour, to be considered a hurricane.

2. Hurricanes in the western Pacific Ocean are called typhoons while hurricanes in the Indian Ocean are known as cyclones.

3. The first hurricane to be seen from space was Hurricane Esther in 1961, spotted by the Tiros III satellite.

4. While hurricane season in the North Atlantic Ocean usually begins in June and ends at the end of November, hurricanes have been reported in the region as early as March and as late as December.

5. The deadliest hurricane to hit the United States was the 1900 Galveston Hurricane, which left at least 8,000 dead, while the deadliest cyclone ever was the 1970 Bhola Cyclone which hit Bangladesh and left at least 300,000 dead.

6. Hurricanes spin counter-clockwise in the northern hemisphere, but they will spin clockwise in the southern hemisphere.

7. The highest sustained wind speed recorded in a hurricane was with Typhoon Tip in 1979, with winds at 191 miles per hour, or 307 kilometers per hour, as it traveled through the western Pacific.

8. The year 2005 set the record for the most Atlantic hurricanes, with 15.

9. Men’s names began being used with hurricanes in addition to women’s names in 1978, and meteorologists will use the names of Greek letters if they run through the alphabet in a season.

— Dr. Bridges is a professor of history and geography living in Arkansas. He can be contacted at drkenbridges@gmail.com. The Science Zone is syndicated nationally by morecontentnow.com, a division of Gatehouse Media.