Tornadoes Case

Tornadoes

David Griswold

April 20, 2014

Natural Disasters

ES117-01-77

DR. Brazell

Tornadoes

A tornado is one of the few natural disasters that have taken place in the Midwest, but its effects can cause devastation that can be felt worldwide.  Tornadoes destroy entire towns. In some cases they will level an entire block, but leave one house standing almost untouched. Their paths can be unpredictable, and cost of the destruction almost immeasurable.  A major natural disaster such as this could wipe out people’s way of life and a food supply that helps to feed the world. In many cases flooding accompanies tornadoes. These super cell storms can drop several inches of water in a very short time. Tornadoes can also destroy water towers leaving communities without drinkable water, knock over power lines leaving communities in the dark and tear open gas lines creating a very high risk of fires and explosions.  

Tornadoes have been somewhat sensationalized in media. There have been books written about tornado events such as The Night of the Twisters by Ivy Ruckman, the story of her cousin’s families bout with the June 3, 1980 Grand Island, Nebraska tornadoes, to movies such as the made for TV movie of the same name and The Wizard of Oz, not to mention the Blockbuster Twister. Although these movies are entertaining, they are far from accurate. “A storm chasers dream come true is to get close enough to a mile-wide tornado to shoot unique video of nature's extreme fury. Maybe even take some close-up measurements of the storm's surroundings, if the science warrants. But never will a chase team be caught racing into the middle of a corn field toward the heart of a whirling funnel no matter what the prize” (Cappella, 2002)

The name tornado is derived from the Spanish verb tornar , which means “ to turn.” A tornado is a rapidly rotating column of air, usually descending from a large thunderstorm. Tornadoes produce the highest wind speeds of any storm. These winds can be in excess of 300 miles per hour (Abbott, p264). Tornadoes can occur in many parts in the world including Australia, Europe, Africa, South America, and North America. They are more common in the United States than in any other part of the world. Nearly 70% of the world’s tornadoes occur in the central United States. Tornadoes have occurred in all 50 states (NOAA,nd). The United States averages more than 1,200 tornadoes each year. Texas gets the award for the most tornadoes each year. I am sure they are thrilled.

 Tornadoes form in unusually violent thunderstorms when there is sufficient instability and wind shear present in the lower atmosphere. Instability refers to unusually warm and humid conditions in the lower atmosphere. With these conditions, air quickly moves upward and forms thunderstorms. Air in the lower troposphere is lifted until it becomes less dense than surrounding air. Once it is less dense, it rises on its own. The speed that is rises depends on the density difference between the air rising and the surrounding air (Haby, nd). Wind shear is the change of wind speed or direction at different heights in the atmosphere. As downdrafts of air within the storm start to block the updraft that is supplying the energy for the tornado, it begins to weaken. The severe thunderstorms which produce tornadoes form where cold dry polar air meets warm moist tropical air. This is most common in a section of the United States known as Tornado Alley. Tornado Alley is a term often used by the media to denote a zone in the Great Plains region of the central United States. This area includes parts of Texas, Oklahoma, Kansas, and Nebraska.