The Science of Deadly Storms
Climate and Weather Conditions Cause Them to Form and Determine How They Move
by Sara Diaz, age 13
Wind is the movement of air. Air moves because of differences in the pressure system. Wind blows from places of higher pressure to places of lower pressure. When it is cold, the air pressure is higher than when it is warm. High winds can form hurricanes, tornadoes, and typhoons.
Hurricanes begin as thunderstorms, when moist air rises above a warm ocean. The combination of wind and water in hurricanes can create a deadly storm.
Forming in the Eastern Atlantic and then spiraling west across the ocean, hurricanes grow larger as they move. Each year, there are about forty-five hurricanes in the Atlantic. If the water is warm enough, thunderstorms and other large storms can converge into a hurricane. In the center of the hurricane is the eye, the focal point of the storm.
Today, satellites can detect every deadly movement of a hurricane. Meteorologists name hurricanes by choosing a male or female name, and then begin tracking the storm as it moves. A hurricane that forms in the Pacific Ocean is called a typhoon.
Compared to hurricanes, tornadoes are small. Tornados are spirals of wind that usually last up to 15 minutes. Tornadoes have average winds of 180 miles per hour. They have a low-pressure center that acts like a vacuum cleaner and can move heavy objects.
Tornadoes appear most often from March to July. They occur mainly in Ohio, lower Missouri, Mississippi river valleys and the Southeast, an area that is referred to as “tornado alley.”
A tornado is set off by a big thundercloud called a “super cell.” A super cell has winds that rotate around the clouds, creating a vortex. The vortex hangs around the cloud’s base near the ground and develops into a tornado.
Hurricanes, tornadoes, and typhoons can all cause severe damage. Tornados can occur in Wisconsin, usually during the spring and early summer.
[Source: The Big Book of Knowledge; Atlas of North America]