Tornadoes rip through Mississippi

Subject : Geography

Section: physical geography

Concept :

A night of tornadoes left behind a trail of devastation in the US state of Mississippi on Friday.
The extremely powerful and large tornadoes destroyed buildings and knocked out power in multiple states.

About Tornadoes

A tornado is a narrow, violently rotating column of air that extends from a thunderstorm to the ground.
Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris.
Tornadoes can be among the most violent phenomena of all atmospheric storms we experience.
Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it.
It is generally accompanied by extreme weather such as heavy downpours, hail storms, and lightning.

What causes tornadoes?

These violent storms occur around the world, but the United States is a major hotspot with about a thousand tornadoes every year.
Although they can occur at any time of the day or night, most tornadoes form in the late afternoon.
By this time the sun has heated the ground and the atmosphere enough to produce thunderstorms.
The most violent tornadoes come from supercells, which are large thunderstorms that have winds already in rotation.
Tornadoes form when warm, humid air collides with cold, dry air.
The denser cold air is pushed over the warm air, usually producing thunderstorms.
The warm air rises through the colder air, causing an updraft.
The updraft will begin to rotate if winds vary sharply in speed or direction.
As the rotating updraft, called a mesocycle, draws in more warm air from the moving thunderstorm, its rotation speed increases.
Cool air fed by the jet stream, a strong band of wind in the atmosphere, provides even more energy.
Water droplets from the mesocyclone’s moist air form a funnel cloud. The funnel continues to grow and eventually it descends from the cloud until it touches the ground to become a tornado.
Once a tornado hits the ground, it may live for as little as a few seconds or as long as three hours.

How tornadoes are forecasted?

Tornadoes are hard to predict because compared to other extreme weather events, they are relatively small.
That makes them difficult to observe. Meteorologists use Doppler radar, weather balloons, satellites, and computer modeling to watch the skies for severe storms and tornadic activity.
Doppler radars record wind speeds and identify areas of rotation within thunderstorms.

Scale to measure the intensity of Tornado

The Fujita Scale (F0 to F5) is used to rate the severity of tornadoes after they occur by the extent of the damage they cause.
F0 is the least intense; F5 the most intense.

Difference between Tornadoes and Funnel Clouds

A tornado is a tightly spinning column of air in contact with the ground beneath a thunderstorm cloud.
In contrast, a funnel cloud spins in mid-air without touching the ground.

Difference between Cyclones and Tornadoes