What is a Tornado?
Tornadoes are usually recognizable by their funnel clouds. Typically, this dynamic, funnel-shaped cloud moves beneath the main storm system. Tornadoes have a condensation funnel made up of water droplets, dust, dirt, and debris that makes them visible almost all of the time. Tornadoes are known by a variety of names, including "whirlwind," "windstorm," "cyclone," "twister," and "typhoon," but they are the most dangerous atmospheric storm.
Formation of Tornadoes
During a supercell storm, the rotation is focused and lowered by downdraughts (descending currents of cold, dense air). In between the formation of tornadoes, rotation may become so concentrated that a narrow column of rapidly spinning air will form. When this violently revolving column of air reaches the ground, a tornado is formed. The presence of a condensation funnel- a funnel-shaped cloud that forms owing to the tornado vortex's much-lowered pressure- makes the tornado observable in the formation of tornadoes. The tornado's visibility may be aided by dust and other debris carried by the powerful winds.
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Cause of Tornado
When warm, moist air collides with cold, dry air, tornadoes emerge. Generally, thunderstorms form when cooler, denser air is pushed over warmer air which is the cause of tornadoes. Updrafts are caused by warm air rising through the cold air. Whenever the wind strength or direction changes, the updraft begins to rotate.
Effects of Tornado
Tornadoes in the United States do roughly $400 million of damage each year and kill about 70 people on average. Homes and businesses are torn apart by extremely violent winds. Winds may also rip the bark off trees, collapse bridges, topple trains, send automobiles and trucks flying, and suck all the water out of a riverbed.
Tornadoes and Severe Storms
Tornadoes are funnel-shaped rotating clouds that arise as a result of violent thunderstorms. They stretch from a thunderstorm to the ground with intense winds averaging 30 miles per hour. They can also accelerate from a standstill to 70 mph in a handful of seconds. Tornadoes in the United States are typically 500 feet across and move for five miles on the ground, with a thunderous roar akin to that of a freight train.
Tornadoes and violent storms pose a threat to the affected regions. Strong wind gusts, lightning strikes, and flash floods are all part of these catastrophic storms. Tornadoes can strike with little or no warning, leaving victims with only seconds to seek shelter. People frequently suffer distresses as a result of tornadoes and severe storms' unpredictability. There are several adverse effects associated with tornadoes and severe storms.
Where do Tornadoes Occur?
The Great Plains of central America are home to the majority of tornadoes, providing a perfect setting for severe thunderstorm formation. Storms form when dry cold air coming south from Canada collides with warm moist air moving north from the Gulf of Mexico in this area, known as Tornado Alley. Tornadoes can occur at any time of year, but they are most common during the spring and summer months when thunderstorms are present. Tornadoes are most common in May and June.
Did you Know?
A tornado is a swirling, funnel-shaped cloud with whirling winds that can reach 300 mph that stretches from a thunderstorm to the ground.
Tornado damage tracks can be more than one mile broad and 50 miles long.
Once on land, tropical storms and hurricanes can be accompanied by tornadoes.
FAQs on Tornado
1. What is a tornado in geographical terms?
A tornado is a violently rotating column of air that extends from the base of a thunderstorm down to the ground. It is often, but not always, visible as a funnel cloud. Tornadoes are considered nature's most violent storms, capable of immense destruction due to their extremely high wind speeds and the powerful updraft at their centre.
2. What atmospheric conditions cause a tornado to form?
Tornadoes form under specific atmospheric conditions, typically within powerful thunderstorms known as supercells. The primary ingredients are:
- Instability: Warm, moist air near the ground lies beneath a layer of cool, dry air. This creates an unstable atmosphere where the warm air rises rapidly.
- Wind Shear: A significant change in wind speed and/or direction with height. This causes the rising air within the storm to begin rotating horizontally.
- Updraft: The strong upward movement of air in the thunderstorm can tilt this rotating horizontal column of air into a vertical position, forming a rotating updraft called a mesocyclone. If this rotation intensifies and a funnel descends to the ground, it becomes a tornado.
3. How are tornadoes classified based on their intensity and speed?
Tornadoes are classified using the Enhanced Fujita (EF) Scale, which rates them from EF0 to EF5 based on the damage they cause, not their physical appearance. Since it's difficult to measure wind speeds directly, scientists estimate the speeds by assessing the extent of the destruction to man-made structures and vegetation. An EF0 might damage trees but leave solid structures intact, while an EF5 can completely level well-built homes and even strip asphalt from roads, with estimated wind speeds exceeding 322 km/h.
4. What is the primary difference between a tornado and a cyclone?
The primary differences between a tornado and a cyclone are scale, duration, and formation process. A tornado is a relatively small-scale, short-lived storm (minutes to an hour) that forms over land from a single thunderstorm. A cyclone (also known as a hurricane or typhoon depending on the region) is a massive, long-lasting storm system (days to weeks) that is hundreds of kilometres wide and forms over warm ocean waters. While a cyclone's overall wind speeds are lower than a tornado's, its vast size and duration cause widespread destruction over a much larger area.
5. Why is a specific region in the USA known as 'Tornado Alley'?
'Tornado Alley' is a colloquial term for a region in the central United States that experiences a disproportionately high frequency of tornadoes. This happens because it is a perfect meeting point for the necessary atmospheric ingredients. Warm, humid air from the Gulf of Mexico flows north, colliding with cool, dry air from the Rocky Mountains and Canada. This clash of air masses creates extreme instability and strong wind shear, providing the ideal conditions for the development of severe supercell thunderstorms that spawn tornadoes, especially during the spring and early summer.
6. What is the difference between a 'tornado watch' and a 'tornado warning'?
Understanding the difference is crucial for safety. A 'tornado watch' means that conditions are favourable for tornadoes to develop in the area. It is a time to be prepared and monitor the weather. A 'tornado warning' is more serious; it means a tornado has been sighted by storm spotters or indicated by weather radar. A warning signifies imminent danger to life and property, and you should take shelter immediately.
7. Have tornadoes been recorded in India, and what are their characteristics here?
Yes, tornadoes do occur in India, although they are much rarer and generally less intense than those in North America. They are most common in the northeastern states, such as West Bengal, Odisha, and Jharkhand, as well as parts of northwestern India, typically during the pre-monsoon season (March to May). These tornadoes are often associated with severe thunderstorms called 'Nor'westers' or 'Kalbaisakhi'. While they can cause significant localized damage, they seldom reach the EF4 or EF5 intensity seen in other parts of the world.
8. Can tornadoes form over water, and what are they called?
Yes, when a rotating column of air forms over a body of water, it is called a waterspout. There are two main types:
- Tornadic Waterspouts: These are essentially tornadoes that form over water or move from land to water. They have the same characteristics as a land-based tornado and can be very dangerous.
- Fair-Weather Waterspouts: These are more common and generally less severe. They form over warm water when the air is unstable, but they are not associated with supercell thunderstorms and usually dissipate quickly upon reaching land.
