What is a Tornado?
Tornado is a smallest piece of hurricane. Tornadoes are vertical funnels of rapidly spinning air. Their winds may top 250 miles (400 kilometers) an hour and can clear a pathway a mile (1.6 kilometers) wide and 50 miles (80 kilometers) long.
Twisters are born in thunderstorms and are often accompanied by hail. Giant, persistent thunderstorms called hurricane spawn the most destructive tornadoes.
These violent storms occur around the world, but the United States is a major hotspot with about a thousand tornadoes every year.
“Tornado Alley,” a region that includes the area in the eastern state of South Dakota, Nebraska, Kansas, Oklahoma, northern Texas, and eastern Colorado, is home to the most powerful and destructive of these storms. U.S. tornadoes cause 80 deaths and more than 1,500 injuries per year.
- A tornado forms when changes in wind speed and direction create a horizontal spinning effect within a storm cell. This effect is then tipped vertical by rising air moving up through the thunderclouds.
- The meteorological factors that drive tornadoes make them more likely at some times than at others. They occur more often in late afternoon, when thunderstorms are common, and are more prevalent in spring and summer. However, tornadoes can and do form at any time of the day and year.
- Tornadoes’ distinctive funnel clouds are actually transparent. They become visible when water droplets pulled from a storm’s moist air condense or when dust and debris are taken up.
- Funnels typically grow about 660 feet (200 meters) wide.
- Tornadoes move at speeds of about 10 to 20 miles (16 to 32 kilometers) per hour, although they’ve been clocked in bursts up to 70 miles (113 kilometers) per hour. Most don’t get very far, though. They rarely travel more than about six miles (ten kilometers) in their short lifetimes.
- Tornadoes are classified as weak, strong, or violent storms. Violent tornadoes comprise only about two percent of all tornadoes, but they cause 70 percent of all tornado deaths and may last an hour or more.
- People, cars, and even buildings may be hurled aloft by tornado-force winds or simply blown away. Most injuries and deaths are caused by flying debris.
- Tornado forecasters can’t provide the same kind of warning that hurricane watchers can, but they can do enough to save lives. Today the average warning time for a tornado alert is 13 minutes. Tornadoes can also be identified by warning signs that include a dark, greenish sky, large hail, and a powerful train-like roar.
Tornadoes form in unusually violent thunderstorms when there is sufficient (1) instability and (2) wind shear present in the lower atmosphere. Instability refers to unusually warm and humid conditions in the lower atmosphere, and possibly cooler than usual conditions in the upper atmosphere.
Even weak tornadoes can pull shingles and siding off of houses. Debris: The second damaging effect of tornadoes is actually from the debris that the storm picks up. … Hail and Lightning: It is not only the wind that causes damage in a tornado, but also the hail and lightning that the storm produces.
An overpass as tornado shelter can put people at a greater risk of being killed or seriously injured by flying debris from the powerful tornado winds. Wind speeds in tornadoes can exceed 200 mph. … A person can even be blown out or carried away from the overpass by the fierce tornado winds.