How fast can twisters go

These violent storms occur around the world, but the United States is a major hotspot with about a thousand tornadoes every year. A tornado is a violently rotating column of air that extends from a thunderstorm to the ground.

It's often portended by a dark, greenish sky. Black storm clouds gather. Baseball-size hail may fall. A funnel suddenly appears, as though descending from a cloud. The funnel hits the ground and roars forward with a sound like that of a freight train approaching.

The tornado tears up everything in its path. Every U. Tornadoes have been reported in Great Britain, India, Argentina, and other countries, but they are most often seen in the United States. Related to tornadoes, waterspouts are weak twisters that form over warm water. They sometimes move inland and become tornadoes.

Dust devils are small, rapidly rotating columns of air that are made visible by the dust and dirt they pick up. Dust devils are not associated with thunderstorms. Either are fire tornadoes , which can spawn from wildfires. The most violent tornadoes come from supercells, large thunderstorms that have winds already in rotation. About one in a thousand storms becomes a supercell, and one in five or six supercells spawns off a tornado.

Tornadoes can occur at any time of year, but they are more common during a distinct season that begins in early spring for the states along the Gulf of Mexico. The season follows the jet stream —as it swings farther north, so does tornado activity.

May generally has more tornadoes than any other month, but April's twisters are sometimes more violent. Farther north, tornadoes tend to be more common later in summer. 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 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. Current Hazards. Local Radar. Rivers and Lakes. Climate and Past Weather. Wisconsin Tornado and Severe Weather Awareness Part 3 - Tornado Classification and Safety Tornadoes can occur in many different shapes and sizes ranging from a few yards to over one mile in width.

Tornado Classification Tornadoes are classified into three broad groups based on their estimated wind speeds and resultant damage: Weak EF0, EF1 Wind speeds of 65 to mph Strong EF2, EF3 Wind speeds of to mph Violent EF4, EF5 Wind speeds of to mph or more For over three decades prior to , the most widely used method worldwide for estimating tornado strength and wind speed was the F-scale developed by Dr.

Theodore Ted Fujita. Since in the U. In the original F-scale, wind speeds were based on calculations of the Beaufort wind scale and had never been scientifically verified in real tornadoes. EF Number 3 Second Gust mph 0 65 to 85 1 86 to 2 to 3 to 4 to 5 Over Enhanced F-scale winds are derived from engineering guidelines but still are only judgmental estimates.

Because: Nobody knows the "true" wind speeds at ground level in most tornadoes, and The amount of wind needed to do similar-looking damage can vary greatly, even from block to block or building to building. Damage rating is at best an exercise in educated guessing. Even experienced damage-survey meteorologists and wind engineers can and often do disagree among themselves on a tornado's strength. One of these violent tornadoes occurred as recently as , peaking in strength east of the village of Oakfield in Fond du Lac county.

Tornado Safety Preparation Know the county you live in. The NWS issues Tornado Warnings that are polygon-based, and may include an entire county, or more likely portions of neighboring counties.

Keep a watchful eye on the sky, and consider postponing outdoor activities. Dust devils are small, rapidly rotating columns of air that are made visible by the dust and dirt they pick up. Dust devils are not associated with thunderstorms. Neither are fire tornadoes , which can spawn from wildfires.

The most violent tornadoes come from supercells, large thunderstorms that have winds already in rotation. About one in a thousand storms becomes a supercell, and one in five or six supercells spawns off a tornado. Tornadoes can occur at any time of year, but they are more common during a distinct season that begins in early spring for the states along the Gulf of Mexico.

The season follows the jet stream —as it swings farther north, so does tornado activity. May generally has more tornadoes than any other month, but April's twisters are sometimes more violent. Farther north, tornadoes tend to be more common later in summer.

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 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. When it touches the ground, it becomes a tornado. Twisters are usually accompanied or preceded by severe thunderstorms and high wlnds. The average is about five minutes. The movie Twister was based upon work NSSL did in the mids using a gallon drum outfitted with various meteorological sensors. NSSL tried for several years to put it in the path of an oncoming tornado, but had minimal success. It is possible that the technology could exist someday; however there are significant challenges with observations such as these.

Read more about Twister science Has every state had a tornado? Yes, although some states have many more tornadoes than others. Are there tornadoes in the Arctic Circle? We are not aware of any tornadoes occurring in the Arctic Circle. Tornadoes need moisture and warm air to form, which is unusual at that latitude. Plus tornadoes or their evidence have to be observed by someone, and the Arctic Circle has few residents! Do tornadoes really stay away from gullies, rivers and mountains?

A gully could actually make a tornado more intense, just as an ice skater spins faster when he or she stands up tall and stretches their arms up straight over their heads. Every major river east of the Rockies has been crossed by a significant tornado, and high elevations in the Appalachians, Rockies, and Sierra Nevada have all experienced tornadoes.

Do tornadoes always come from a wall cloud? A wall cloud is not always present. It is also possible that you cannot see a wall cloud because of your viewing angle or low level clouds. What does a tornado sound like? People who have been in a tornado say it sounds like a jet engine or a freight train and is very loud. They said it hurt their ears, but they were more worried about what might happen to them than they were about the pain in their ears. Can tornadoes be stopped? You have to consider that the tornado is part of something bigger: the supercell thunderstorm.

Unless you disrupt the supercell thunderstorm itself, you would likely have another tornado, even if you were able to destroy the first. The thunderstorm's energy is much greater than the tornado.

No one has tried to disrupt the tornado because the methods to do so could likely cause even more damage than the tornado. Detonating a nuclear bomb, for example, to disrupt a tornado would be even more deadly and destructive than the tornado itself.

Lesser tactics like deploying huge piles of dry ice or smaller conventional weaponry would be too hard to get into the right place fast enough, and would likely not have enough impact to affect the tornado much anyway. Thunderstorms, and all of the hazards they produce, are part of a natural earth cycle.

Taking actions sufficient to disrupt this cycle could lead to unintended consequences. What is the difference between a tornado watch and a tornado warning? A tornado watch defines an area where tornadoes and other kinds of severe weather are possible in the next several hours. It means that you need to be alert, and be prepared to go to safe shelter if tornadoes happen or a warning is issued.

Tune in to local TV, radio or internet for more information. A tornado warning means that a tornado has been spotted, or that Doppler radar shows a thunderstorm circulation which can spawn a tornado. When a tornado warning is issued for your area, seek safe shelter immediately. The Storm Prediction Center issues tornado and severe thunderstorm watches. Your local National Weather Service office issues tornado warnings, as well as thunderstorm warnings, which include the possibility of tornadoes.

What would it be like to be in the eye of a tornado? This is a fiction largely caused by the movie Twister. How many tornadoes hit the US each year?