Tornadoes

A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud.


Size and Shape

  • tornadoes can be many different shapes and sizes.

  • Small relatively weak landspouts may be visible only as a small swirl of dust on the ground.

  • If the winds are greater than 40mph, the circulation is considered a tornado.

  • A tornado with a nearly cylindrical profile and relative low height is sometimes referred to as a "stovepipe" tornado.

  • In the united states,tornadoes are around 500 feet across on average and stay on the ground for 5 miles.

  • Yet, their is a wide range of tornado sizes.

  • Weak tornadoes or strong yet dissipating tornadoes, can be exceedingly narrow.

  • Tornadoes can have a wide range of colors, depending on the environment in which they form.

  • The ones that form in a dry environment can be nearly invisible, marked only by swirling debris at the base of the funnel.

  • While traveling over a body of water, they can even turn blue.

  • Funnels which move slowly, ingesting a lot of debris and dirt, are usually darker, taking on the color of debris.

  • Tornadoes in the great plains can turn red because of the reddish tint to the soil.

  • Tornadoes in mountainous areas can travel over snow-covered ground, turning white.

  • Lighting conditions are a major factor in the appearance of a tornado.


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Rotation

  • Tornadoes normally rotate cyclonically in direction.

  • Approximately 1% of tornadoes rotate in an anticyclonic direction in the northern hemisphere.

  • Typically, systems as weak as landspouts and gustnadoes can rotate anticyclonically, and usually only those which form on the anticyclonic shear side of the descending in a cyclonic supercell.


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How they form

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before thunderstorms develop a change in wind direction and an increasing height, creates an invisible, horizontal spinning effect in the lower atmosphere. then rising air within the thunderstorm 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. a lower cloud identifies an area of rotation known as a rotating wall cloud. this area is often nearly rain-free. moments later a strong tornado develops in this area. softball-size hail an damaging "straight-line" winds also occurred with this storm.

tornadoes usually result from a very large thunderstorm. cold air and warm air combine, and the cold air goes down as the warm air rises. this warm air eventually twist into a spiral, forming a funnel cloud. as the sky turns very dark green color, the tornado begins in a path of destruction.







Strength of tornadoes

  • Gale tornadoes


    light damage=
  • Moderate tornado


    moderate damage.=
  • Significant tornado


    considerable damage.=
  • Severe tornado =severe damage.

  • Devastating tornado


    devastating damage.
  • Incredible tornado


    incredible damage.
  • The damage from tornadoes all depend in how strong the winds are.

  • Tornadoes winds can be as high as 300mph.

Radar

  • Many country's have came up with the technique of weather radar's.
  • Weather radar's detect tornadoes.
  • In the United States Doppler radars are used to measure the velocity and radial direction of winds in a storm.

Meteorology

  • Meteorology is a study of young science and tornadoes.

  • Although tornadoes have been being researches for about 140 years and more intensivly the last 60 years their still soem what a mystery.

  • Pedicting tornadoes is still sort of a problem.

  • Meteorologist still can't tell the intensity and longevity of a tornado.

Safety

  • when a tornado warning is issued you should go to a basement.

  • should always have a plan when a warning is issued.

  • if you are in a storm, most of them should have storm cellars.

  • in your house you should always have a weather radio.

  • if no basement, cellar, or sturdy place is not around get down in a low ditch.

links
http://www.spc.noaa.gov/faq/tornado/

http://www.noaa.gov/tornadoes.html

http://www.chaseday.com/tornadoes.htm
http://abcnews.go.com/US/tornadoes-storms-tear-south-292-dead/story?id=13474955