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Tornadoes are furiously spinning columns of air that collide with the Earth‘s surface, a cumulonimbus cloud, or, in rare cases, the bottom of a cumulus cloud. It is also known as a twister, whirlwind, or cyclone. However, in meteorology, a cyclone is defined as a weather system with a low-pressure depression in the center with winds blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern.
See the fact file below for more information about Tornadoes, or download the comprehensive Tornado worksheet pack, which contains over 11 worksheets and can be used in the classroom or homeschooling environment.
Key Facts & Information
OVERVIEW
- Tornadoes arise in various forms and sizes. They are frequently seen as a condensation funnel emanating from the base of a cumulonimbus cloud, with a cloud of swirling debris and dust beneath it.
- Tornadoes possess wind speeds of less than 180 km/h (110 mph) and around 80 m (250 ft) wide and can travel for many kilometers (a few miles) before collapsing.
- Tornadoes may reach wind speeds of more than 480 km/h (300 mph), have diameters of more than 3 km (2 miles), and remain on the ground for more than 100 km (60 miles).
DEFINITION
- Tornadoes are fiercely spinning columns of air in contact with the ground, either above or beneath a cumuliform cloud, and are commonly (but not always) observed as a funnel cloud.
- A vortex must contact the surface and the cloud base to be classed as a tornado. The phrase is not precisely defined; for example, whether several touchdowns of the same funnel constitute different tornadoes is debatable.
- Tornadoes are wind vortices, not condensation clouds.
FUNNEL CLOUD
- The external pressure induced by the high wind speeds (as explained by Bernoulli‘s principle) and quick rotation (due to cyclostrophic balancing) frequently cause water vapor in the air to condense into cloud droplets owing to adiabatic cooling. As a result, an apparent funnel cloud or condensation funnel forms.
- There is a substantial argument over what constitutes a funnel cloud and a condensation funnel.
- According to the Glossary of Meteorology, a funnel cloud is any spinning cloud pendant from a cumulus or cumulonimbus; hence, most tornadoes fit this definition.
- Many meteorologists describe a funnel cloud as a spinning cloud that is not coupled with strong winds on the ground. In contrast, a condensation funnel is a general word for any spinning cloud below a cumuliform cloud.
- Tornadoes frequently start as funnel clouds with no concomitant high winds at the surface, and not all funnel clouds develop into tornadoes.
- Because most tornadoes create severe winds at the surface while the visual funnel remains above ground, distinguishing between a funnel cloud and a tornado from a distance can be difficult.
OUTBREAKS AND FAMILIES
- Often, a single storm may create multiple tornadoes simultaneously or sequentially. A “tornado family” is a cluster of tornadoes formed by the same storm cell, and several tornadoes can develop from the same large-scale storm event.
- It is termed a tornado outbreak if there is no pause in activity. A tornado outbreak sequence, also known as an extended tornado outbreak, is many consecutive days with tornado outbreaks in the same approximate area (caused by several meteorological systems).
SHAPE
- Most tornadoes resemble a narrow funnel a few hundred meters (yards) across, with a tiny cloud of debris near the ground. Tornadoes might be entirely concealed by rain or dust. These tornadoes are particularly deadly because even expert meteorologists may miss them.
- Tiny, weak landspouts may only be noticed as a small swirl of dirt on the ground. Although the condensation funnel may not prolong to the ground, the circulation is classified as a tornado if the associated surface winds exceed 64 km/h (40 mph).
- A tornado has a roughly cylindrical form and a low height is known as a “stovepipe” tornado. Gigantic tornadoes that appear at least as broad as their cloud-to-ground height might resemble large wedges lodged in the ground and are hence known as “wedge tornadoes” or “wedges,” with the “stovepipe” categorization also used if it otherwise matches that description.
- A wedge tornado can be so large that it looks like a block of black clouds, more expansive than the range from the cloud base to the ground, and even expert storm observers may be unable to distinguish the difference from a distance. Many, but not all, significant tornadoes are wedges.
- Tornadoes in dissipation can resemble thin tubes or ropes and frequently coil or twist into intricate patterns. When these tornadoes “rope out” or become a “rope tornado,” the length of their funnel grows, causing the winds within the funnel to lessen owing to the conservation of angular momentum.
- Tornadoes with several vortices might seem like a family of swirls orbiting a common core. They can be entirely buried by condensation, dirt, and debris and appear as a single funnel.
SIZE
- Tornadoes in the United States often have a width of 500 feet (150 meters) and can travel 5 miles on the ground (8.0 km).
- Tornadoes, on the other hand, come in a variety of sizes. Tornadoes, weak or violent but fading, can be extremely narrow, measuring only a few feet or a couple of meters wide. One tornado had a damaged path barely 7 feet (2.1 m) long.
APPEARANCE
- Tornadoes may have a broad spectrum of colors based on their surroundings. Those that develop in arid conditions might be practically undetectable, with only spinning debris at the funnel’s base to distinguish them.
- Condensation funnels with little or no debris can range from gray to white. Tornadoes can become white or blue when passing over water (as a waterspout).
- Slow-moving funnels that consume a lot of trash and dirt are generally darker and reflect the particles’ color. Tornadoes on the Great Plains can turn red because of the reddish hue of the soil, but tornadoes in the mountains can pass across snow-covered land and turn white.
ROTATION
- Tornadoes typically rotate cyclically (when viewed from above, this is counterclockwise in the northern hemisphere and clockwise in the southern). While large-scale storms usually spin cyclically as a result of the Coriolis effect, thunderstorms and tornadoes are so tiny that the direct influence of the Coriolis effect is negligible, as seen by their high Rossby numbers.
- Even when the Coriolis effect is ignored, supercells and tornadoes spin cyclically in computer simulations. Low-level mesocyclones and tornadoes rotate due to complicated mechanisms inside the supercell and the surrounding environment.
LIFE CYCLE
SUPERCELL RELATIONSHIP
- Tornadoes are frequently formed by a kind of thunderstorm known as a supercell. Mesocyclones are areas of structured rotation a few km up in the atmosphere, typically 1.6-9.7 km (1-6 miles) wide. Supercells produce the most powerful tornadoes (EF3 to EF5 on the Enhanced Fujita Scale).
- Tornadoes are typical in such storms, as are torrential rain, frequent lightning, high wind gusts, and hail.
- Most supercell tornadoes have a predictable life cycle that begins when rising rainfall drags a region of rapidly falling air known as the rear flank downdraft (RFD).
- This downdraft increases as it reaches the ground, dragging the supercell’s whirling mesocyclone.
FORMATION
- As the mesocyclone descends below the cloud base, it absorbs chilly, moist air from the storm’s downdraft zone, and the confluence of warm air in the updraft and cool air results in the formation of a revolving wall cloud.
- The RFD also concentrates the base of the mesocyclone, forcing it to suck air from a smaller and smaller region on the ground. As the updraft strengthens, it generates a low-pressure zone near the surface. It forces the concentrated mesocyclone downward, creating an evident condensation funnel.
- The RFD hits the ground as the funnel falls, spreading outward and forming a gusting front that can cause significant damage a long distance away from the tornado.
- Within a few minutes of the RFD reaching the ground, the funnel cloud usually begins wreaking damage on the ground (becoming a tornado).
MATURITY
- Initially, the tornado is powered by warm, moist air rushing inward and expands until it reaches the “mature stage.”
- It can range from a few minutes to more than an hour, and a tornado frequently does the most damage during that period and, in exceptional circumstances, can reach more than 1.6 km (1 mile) broad. The low-pressure environment at the tornado’s base is critical to the system’s survival.
- Meanwhile, the RFD, now a chilly surface wind region, begins to wrap around the tornado, cutting off the input of warm air that had previously fuelled it.
- The movement inside the tornado’s funnel is downward, bringing water vapor from above clouds, and it is in contrast to the upward trend of water vapor from the warm ocean below that occurs during storms. As a result, the tornado’s energy is provided by the cloud above. The intricate mechanism is described.
DISSIPATION
- As the RFD entirely wraps around the tornado, cutting off its air supply, the vortex weakens, becoming thin and rope-like.
- It is the “dissipating stage,” which usually lasts only a few minutes before the tornado dissipates.
- During this stage, the tornado’s form is heavily impacted by the parent storm’s winds and can be blown into unique designs. Even when the tornado is fading, it may still cause damage.
- The storm is shrinking into a rope-like tube, and winds may rise at this time owing to angular momentum conservation.
- Although this is a commonly recognized hypothesis for how most tornadoes create, live, and die, it does not explain how smaller tornadoes, such as landspouts, long-lived tornadoes, or tornadoes with numerous vortex forms. These all have various processes that impact their formation, but most tornadoes follow a similar pattern.
TYPES OF TORNADO
MULTIPLE VORTEX TORNADO
- A multiple-vortex tornado is one in which two or more pillars of spinning air swirl around their axes while also rotating around a common core.
- A multi-vortex structure may develop in any circulation, most commonly seen in solid tornadoes.
- These vortices frequently produce minor regions of more significant damage along the tornado’s main course. It is separate from a satellite tornado, a tiny tornado that occurs exceptionally close to a big, powerful tornado trapped within the same mesocyclone.
- The satellite tornado may appear to “orbit” (thus the name) the enormous tornado, creating the illusion of a single substantial multi-vortex tornado. On the other hand, a satellite tornado has a separate circulation that is significantly smaller than the primary funnel.
WATERSPOUT
- The National Weather Service describes a waterspout as a tornado over water. Researchers often distinguish between “fair weather” waterspouts and tornadic (i.e., connected with a mesocyclone) waterspouts.
- Fair weather waterspouts, related to dust devils and landspouts, are less severe but significantly more prevalent.
- They develop over tropical and subtropical oceans at the bottoms of cumulus congestus clouds. They feature fair winds and smooth laminar walls and move at a snail’s pace. They are most frequently seen in the Florida Keys and the northern Adriatic Sea.
- Tornadic waterspouts, on the other hand, are more incredible tornadoes over water. They occur over water in the same way as mesocyclonic tornadoes, or they are stronger tornadoes that traverse over water.
- They are more dangerous than fair-weather waterspouts because they arise from strong thunderstorms and may be significantly more violent, quicker, and longer-lived.
- Waterspouts usually are not listed in official tornado statistics unless they cause land damage, while some European meteorological services combine waterspouts and tornadoes.
LANDSPOUT
- A landspout, also known as a dust-tube tornado, is a tornado that is not coupled with a mesocyclone. The term derives from its description as a “fair weather waterspout on land.”
- Waterspouts and landspouts have numerous similarities, including relative frailty, a short lifetime, and a tiny, smooth condensation funnel that seldom reaches the surface.
- Because their physics differ from actual mesoform tornadoes, landspouts produce a distinctly laminar dust cloud when they collide with the ground. Though they are typically smaller than conventional tornadoes, they may create intense winds that can cause significant damage.
SIMILAR CIRCULATION
GUSTNADO
- A gustnado, also known as a gust front tornado, is a short, vertical whirl caused by a gust front or downburst. There is significant controversy about whether a gustnado is tornadoes because they are not tied to a cloud base.
- They arise when fast-moving, cold, dry outflow air from a thunderstorm blows through a mass of immobile, warm, moist air at the outflow boundary, causing a “rolling” effect (often exemplified through a roll cloud).
- If there is enough low-level wind shear, the spin can be directed vertically or diagonally and contact the Earth. As a result, there is a gustnado.
DUST DEVIL
- A dust devil (also called a whirlwind) is a vertical spinning column of air that resembles a tornado. They originate under clear skies and are no more significant than the weakest tornadoes.
- On a hot day, they occur when a powerful convective updraft forms near the ground. If there is sufficient low-level wind shear, the column of heated, ascending air can create a minor cyclonic motion visible near the base.
- Tornadoes are not considered since they develop during clear weather and are unrelated to clouds. They can, however, cause significant damage on occasion.
FIRE WHIRLS
- Tornado-like circulations can form near any extreme surface heat source, and fire whirls are those that develop near severe flames. Except in rare events, they link to a pyrocumulus or other cumuliform cloud above and are not called tornadoes.
- Tornadoes connected with thunderstorms are typically stronger than fire whirls. They can, however, cause considerable harm.
STEAM DEVILS
- A steam devil is a revolving updraft that ranges in width from 50 to 200 meters (160 to 660 feet).
- These structures do not have intense wind speeds and only rotate a few times each minute. Steam demons are pretty rare.
- They are most commonly caused by smoke from a power plant’s chimney. Hot springs and deserts may also be appropriate places to form a tighter, faster-rotating steam devil.
- The phenomena can occur when chilly arctic air travels over relatively warm water.
Tornado Worksheets
This bundle contains 11 ready-to-use Tornado Worksheets that are perfect for students who want to learn more about a tornado, which is a tube of violently spinning air that touches the ground. Wind inside the tornado spins fast, but the actual ‘circle’ of wind around them is massive. This makes tornadoes very dangerous.
Download includes the following worksheets:
- Tornado Facts
- Tornado True Or False
- How Tornadoes Occur
- Spot The Tornadoes
- All About Tornado Alley
- Tornado Crossword Puzzle
- Tornado File Report
- Fujita Scale
- Signs of a Tornado Threat
- Tornado Tips
- News Flash
Frequently Asked Questions
What is a tornado?
Tornadoes are furiously spinning columns of air that collide with the Earth’s surface, a cumulonimbus cloud, or, in rare cases, the bottom of a cumulus cloud.
How do tornadoes form?
As the mesocyclone descends below the cloud base, it absorbs chilly, moist air from the storm’s downdraft zone, and the confluence of warm air in the updraft and cool air results in the formation of a revolving wall cloud.
What is a waterspout tornado?
The National Weather Service describes a waterspout as a tornado over water. Researchers often distinguish between “fair weather” waterspouts and tornadic (i.e., connected with a mesocyclone) waterspouts.
What is a multiple-vortex tornado?
A multiple-vortex tornado is one in which two or more pillars of spinning air swirl around their axes while also rotating around a common core.
Why dust devil or whirlwind is not considered a tornado?
A dust devil (also called a whirlwind) is a vertical spinning column of air that resembles a tornado. They originate under clear skies and are no more significant than the weakest tornadoes. Tornadoes are not considered since they develop during clear weather and are unrelated to clouds.
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Link will appear as Tornado Facts & Worksheets: https://kidskonnect.com - KidsKonnect, October 28, 2017
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