Tornadoes





What are tornadoes?

Tornadoes are funnels of fast spinning air that can reach up to 318 mph. Tornadoes are made in thunderstorms. The tornadoes that come from supercells cause the most damage.



How do they form?

Tornadoes form during the early stage of a severe thunderstorm in a cumulonimbus cloud. Rising air moves the rotating air from horizontal to vertical, then an area 2-6 miles wide spreads through the storm. The rotating wall cloud forms and the tornado comes after. Tornadoes usually start out clear until they pick up debris and dust. Two or more may happen at the same time.



How are they measured?

Fujita scales are used to measure tornadoes. The scale ranges from F0 to F5. F0 causes the little destruction, and F5 causes the most.


Different types of tornadoes.

Waterspout

A waterspout is a tornado that happens over bodies of water in warm places near the equator. They are weaker than most of the tornadoes on land. Waterspouts don't suck up water like many people think. They have a five-part life cycle: A dark spot forms on the water surface, spiral pattern on the water surface, formation of a spray ring, development of the visible condensation funnel, and then die out.

waterspout-1.jpg
Waterspout

Land spout

Land spouts look a lot like waterspouts. They both show to have a smooth, tube-like shape. They are known as dust-tube tornadoes by the National Weather Service. Some last up to 15 minutes, and have caused F3 damage.

Multiple vortex tornado

Multiple vortex tornado is a tornado that has several vortices rotating around inside of it. The multiple vortices are usually only visible when the tornado is first forming. They aren't super cells like regular tornadoes.

Gustnado

This is a type of short lived cloud that comes from a severe thunderstorm. They are formed from the downdraft gust of a strong thunderstorm. Gustnadoes are not like tornadoes. They can last from a few seconds to a few minutes. Gustnadoes usually have the winds of an F0 or F1 tornado. They are most common in the Great Plains and the Midwest of the United States.

Dust Devil

Dust Devils usually have long lives and can be one thousand meters tall and ten meters wide to a half a meter wide and only a few meters tall. Dust Devils are usually weak and don't cause damage.

Fire whirl

Fire whirls are rare and can make fires more dangerous. The most dangerous ones are formed when an updraft is present in a wildfire. They range from thirty to two hundred feet tall and about ten feet wide. They also can have winds up to one hundred and sixty miles per hour and can last twenty minutes.

Where do tornadoes occur?

Tornado season goes from March to August, but tornadoes can form any time of the year. May and June are the months when tornadoes occur the most. Tornadoes form the most in tornado alley, where cold air from Canada and warm air from the Gulf of Mexico meet. Tornado alley is in Oklahoma, Texas, Kansas, and Nebraska. States where tornadoes are common but are not in tornado alley are Illinois, Indiana, Wisconsin, Michigan, South Dakota, Missouri, Iowa, Alabama, Mississippi, South Carolina, and Georgia. Tornadoes in Southern Florida, South Carolina, and Georgia are usually formed by hurricanes. Tornadoes are known to occur in other places such as Australia, Europe, Africa, Asia, and South America.external image haz_tornado_alley.gif

The difference between a tornado watch and a tornado warning

A tornado watch watch means that there's a possibility that there is a tornado in your area. A tornado warning means that a tornado was seen or detected by radar in an area. During a tornado watch, there is usually dark green or gray skies, and there's also large hail. A tornado warning means that there is rotation in the clouds that could turn into a tornado.

Tornado safety tips

There are all kinds of different ways to stay safe during a tornado. Some ways are:
Listen to local radio or news reports to learn what the storms in your area will develop into.
Know the difference between a tornado watch- conditions are right for a tornado to form; and a tornado warning- rotation has been spotted.
Go into a basement.
Watch out for fallen power lines
Listen to the radio to find out if it is safe.



Sources


http://geography.about.com/od/physicalgeography/a/fujitascale.htm

http://www.nssl.noaa.gov/edu/safety/tornadoguide.html


http://www.windows.ucar.edu/tour/link=/earth/Atmosphere/tornado/alley.html

http://www.theweatherchannelkids.com/weather_ed/weather_encyclopedia/tornadoes/types_of_tornadoes/

http://nashville.about.com/od/weather/a/tornadowatch.htm

http://www.quakekare.com/emergency-preparedness/tornado-preparedness.html?gclid=CKDYsbqvz6ECFRQN2god-BJYMA