A tornado is a violently rotating column of air which is in contact
with both a cumulonimbus cloud base and the surface of the earth.
Tornadoes can come in many sizes, but are typically in the form of a
visible condensation funnel, with the narrow end touching the earth.
Often, a cloud of debris encircles the lower portion of the funnel.
Most tornadoes have winds of 110 mph (175 km/h) or less, are
approximately 250 feet (75 meters) across, and travel a few miles
(several kilometers) before dissipating. However, some tornadoes can
have winds of more than 300 mph (480 km/h), be more than a mile
(1.6 km) across, and stay on the ground for dozens of miles (more than
100 kilometers). Tornadoes have been observed on every continent
except Antarctica; however, most of the world's tornadoes occur in the
United States. Other areas which commonly experience tornadoes include
New Zealand, western and southeastern Australia, south-central Canada,
northwestern and central Europe, Italy, south-central and eastern
Asia, east-central South America, and Southern Africa.
Read the rest of this article:
http://en.wikipedia.org/wiki/Tornado
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Today's selected anniversaries:
1626:
Peter Minuit bought Manhattan in exchange for trade goods valued at 60
guilders.
(
http://en.wikipedia.org/wiki/Peter_Minuit)
1822:
Ecuadorian War of Independence: Troops led by Antonio José de Sucre
secured the independence of Quito from Spain in the Battle of
Pichincha.
(
http://en.wikipedia.org/wiki/Battle_of_Pichincha)
1883:
The Brooklyn Bridge, at the time the longest suspension bridge in the
world, was opened.
(
http://en.wikipedia.org/wiki/Brooklyn_Bridge)
1941:
World War II: The German battleship Bismarck sank the British
battlecruiser HMS Hood in the Battle of the Denmark Strait.
(
http://en.wikipedia.org/wiki/German_battleship_Bismarck)
(
http://en.wikipedia.org/wiki/HMS_Hood_(51))
1962:
Project Mercury: American astronaut Scott Carpenter orbited the Earth
three times in the Aurora 7 space capsule.
(
http://en.wikipedia.org/wiki/Scott_Carpenter)
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Wikiquote of the day:
Freedom of expression is the matrix, the indispensable condition, of
nearly every other form of freedom. -- Benjamin N. Cardozo
(
http://en.wikiquote.org/wiki/Benjamin_N._Cardozo)