Weather
By: Summer Jeanes
Lightning Strike
Lightning is an electric current, and just like the electricity lurking in the outlets in your house, it can be deadly. Have you ever gotten a shock by shuffling across a carpet and then touching something made of metal? Then you've experienced the same process that makes lightning.
Within a thundercloud, many small bits of ice bump into each other as they swirl around in the air. All those collisions create an electrical charge, just like the one that built up in you when you crossed the carpet.
After a while, the whole cloud fills up with electrical charges (usually with a negative charge closest to the earth). Since opposites attract each other, that causes a positive charge to build up on the ground beneath the cloud. The ground's electrical charge concentrates around anything that sticks up, such as mountains, lone trees, people, or even blades of grass. The charge streaming up from these points eventually connects with a charge reaching down from the clouds, and--zap!--lightning strikes.
The intense heat of the lightning bolt causes the surrounding air to explode outward with a gigantic boom--thunder.
Hurricane
A hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph. Each hurricane usually lasts for over a week, moving 10-20 miles per hour over the open ocean. Hurricanes gather heat and energy through contact with warm ocean waters. Evaporation from the seawater increases their power. Hurricanes rotate in a counter-clockwise direction around an "eye" in the Northern Hemisphere and clockwise direction in the Southern Hemisphere. The center of the storm or "eye" is the calmest part. It has only light winds and fair weather. When they come onto land, the heavy rain, strong winds and large waves can damage buildings, trees and cars.
Tornado
Most tornadoes form from thunderstorms. You need warm, moist air from the Gulf of Mexico and cool, dry air from Canada. When these two air masses meet, they create instability in the atmosphere. A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.