tornado is a type of intense
rotary storm. According to the Glossary
of Meteorology, a
tornado is- "a
violently rotating column of
air, in contact with the ground, either pendant from a cumuliform
cloud or underneath a cumuliform cloud, and often (but not always)
visible as a
A funnel cloud, which
is a type of
condensation cloud, is
structure and extends
down from a cumuliform
by a rotating
column of air towards
the ground. It may or
may not touch
ground. If it touches
the ground it is called
column of air
is a ‘vortex’.
This diagram shows a funnel
that does not touch
Tornadoes are much stronger
dust devils, hurricanes or mid-latitude cyclonic storms.
Practically it is the most violent of all the vortex storms we see in
Storms are marked by disturbance and strong wind in the atmosphere.
storm accompanies thunder and lightning, it is called thunderstorm.
tornado, a strong up drift of air exists
and the pressure remains very low at
the core. So, if it is strong enough, it can suck in (up) almost
comes into it’s path. The tornado is not always visible but the
debris around the funnel makes it visible.
In a small scale, tornado is the most
atmospheric phenomenon. The vortex of a tornado is only a few hundred
wide on an average. The wind speed inside a tornado normally ranges
from 40 mph to as
high as 300
mph. Speeds higher than this are actually rare. Depending on its speed,
tornadoes are rated using F-scale.
A funnel cloud that is
Tornadoes may rotate both cyclonically
anti-cyclonically, but cyclonic rotation is most common. It can be
mentioned here that if a wind swirl is counter-clockwise in the
hemisphere and clockwise in the southern hemisphere, it is called
cyclonic. But contrary to a common belief, coriolis force or
earth’s rotation has no role in the
of rotation of a tornado.
: Phys-645, Fall-2007, UAF.
Animation for 'Home' - taken from www.animationlibrary.com