Tornado
Information

Waterspout

A waterspout is a column of rotating
wind that develops downward from a line of cumulus clouds to a body of
water. A Cumulus cloud must be present for a waterspout to occur. The
contrast of cold air overlying warm water provides a critical element
leading to a waterspout event. Spouts can pack winds up to 200 miles per
hour and will move across the water up to 10 to 15 miles per hour. They
have been observed to reach heights of up to 10,000 feet.

Dust Devil

Dust devils are swirls that go upward to
fizzle out in clear air; they aren't attached to clouds. While they are
most commonly found on deserts and form when air at the ground becomes
much hotter than the air above. The lighter, hot air begins rising and
takes on a whirling motion that carries dust and sand upward. Top wind
speeds seem to be around 60 mph.

Gustnadoes

"Gustnadoes" are weak vortices
that are not connected to the cloud base, and by definition are not
tornadoes. They are relatively shallow vortices associated with intense,
small-scale shear in a thunderstorm gust front. They are not directly
linked with rotation in the thunderstorm itself. Because they can
produce whirling dust clouds (sometimes with small debris), they are
very often misidentified as tornadoes. It takes a very alert and
experienced spotter to tell the difference sometimes.

"Supercell"
tornadoes

"Supercell"
tornadoes are the largest and most most dangerous. They spin up under
rotating storm and have winds up to 300 mph. They could be as much as a mile
wide and last for
hours.

Landspouts

Narrow vortex forms over 
land
under growing cumulus cloud; winds might reach 140 mph; last several
minutes.

Sources:

http://desmoinesregister.com/extras/weather/torntypes.html

http://www.chaseday.com/tornadoes.htm

http://www.onlineweather.com/v4/data/Tornadoes.html