Why is U.S.A. the most common place where tornadoes exist?

Answer 1

The United States has the most tornadoes of any country, about four times more than estimated in all of Europe, not including waterspouts. This is mostly due to the unique geography of the continent. North America is a relatively large continent that extends from the tropical south into arctic areas, and has no major east-west mountain range to block air flow between these two areas. In the middle latitudes, where most tornadoes of the world occur, the Rocky Mountains block moisture and atmospheric flow, allowing drier air at mid-levels of the troposphere, and causing cyclogenesis downstream to the east of the mountains. The desert Southwest also feeds drier air and the dry line, while the Gulf of Mexico fuels abundant low-level moisture. This unique topography allows for many collisions of warm and cold air, the conditions that breed strong, long-lived storms many times a year. A large portion of these tornadoes form in an area of the central United States known as Tornado Alley.This area extends into Canada, particularly Ontario and the Prairie Provinces. Strong tornadoes also occasionally occur in northern Mexico.

The United States averages about 1,200 tornadoes per year. The Netherlands has the highest average number of recorded tornadoes per area of any country (more than 20, or 0.0013 per sq mi (0.00048 per km²), annually), followed by the UK (around 33, or 0.00035 per sq mi (0.00013 per km²), per year), but most are small and cause minor damage. In absolute number of events, ignoring area, the UK experiences more tornadoes than any other European country, excluding waterspouts.

Bangladesh and surrounding areas of eastern India suffer from tornadoes of equal severity to those in the US with more regularity than any other region in the world, but these tend to be under-reported due to the scarcity of media coverage in third-world countries. They kill about 179 people per year in Bangladesh, much more than in the US. This is likely due to the density of population, poor quality of construction, lack of tornado safety knowledge, and other factors.[46] Other areas of the world that have frequent tornadoes include South Africa, parts of Argentina, Paraguay, and southern Brazil, as well as portions of Europe, Australia and New Zealand, and far eastern Asia.

Tornadoes are most common in spring and least common in winter. Since autumn and spring are transitional periods (warm to cool and vice versa) there are more chances of cooler air meeting with warmer air, resulting in thunderstorms. Tornadoes can also be caused by landfalling tropical cyclones, which tend to occur in the late summer and autumn. But favorable conditions can occur at any time of the year.

Tornado occurrence is highly dependent on the time of day, because of solar heating. Worldwide, most tornadoes occur in the late afternoon, between 3 and 7 pm local time, with a peak near 5 pm. However, destructive tornadoes can occur at any time of day. The Gainesville Tornado of 1936, one of the deadliest tornadoes in history, occurred at 8:30 am local time

Answer 2

This is because the landform of the United States is well set up for severe storms and tornadoes. You have the great plains which has very little elevation change from the Gulf of Mexico northward into Canada. The generally north-south orientation of the Rocky Mountains combines with generally westerly winds in the upper atmosphere to produce low pressure areas over the high plains just east of the mountains. This draws moisture northward from the Gulf, while also pulling dry air off the mountains eastward. The boundary between these two air masses, known as a dry line, is a good focusing area for thunderstorm development. The southerly low-level winds and the westerly upper level winds result in shear that acts on thunderstorms, creating rotation in the stronger storms. From there, if other factors come together properly, tornadoes result. Cold air masses can also sweep down the plains from the north, but this scenario
is a bit less likely to produce tornadic storms.

Answer 3

Think about it.

In the Great Plains you have warm moist air from the Gulf of Mexico and then dry cold air coming from Central Canada going against each other. Which is one cause for tornadoes.

In almost every part of the United States except for the west coast you get supercell thunderstorms which are thunderstorms that are long lived and have traveled long distances and have cloud rotation.

Another cause is tropical cyclones. EVERY PART OF THE EAST COAST & THE GULF COAST IS AT RISK FOR A TROPICAL CYCLONE. Due to the counter-clockwise rotation funnels start to form and eventually touchdown as tornadoes.

This is why the United States gets the most tornadoes every year with over 800 every year.

Answer 4

To Learn More See The Folowing links
http://www.nssl.noaa.gov/edu/safety/tornadoguide.html
Torndos
http://www.srh.noaa.gov/srh/jetstream/tstorms/tornado.htm
Thunderstorms
http://www.srh.noaa.gov/srh/jetstream/tstorms/tstorms_intro.htm

Although tornadoes occur in many parts of the world, these destructive forces of nature are found most frequently in the United States east of the Rocky Mountains during the spring and summer months. In an average year, 800 tornadoes are reported nationwide, resulting in 80 deaths and over 1,500 injuries. A tornado is defined as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. Damage paths can be in excess of one mile wide and 50 miles long. Once a tornado in Broken Bow, Oklahoma, carried a motel sign 30 miles and dropped it in Arkansas!

What causes tornadoes?
Thunderstorms develop in warm, moist air in advance of eastward-moving cold fronts. These thunderstorms often produce large hail, strong winds, and tornadoes. Tornadoes in the winter and early spring are often associated with strong, frontal systems that form in the Central States and move east. Occasionally, large outbreaks of tornadoes occur with this type of weather pattern. Several states may be affected by numerous severe thunderstorms and tornadoes.

During the spring in the Central Plains, thunderstorms frequently develop along a "dryline," which separates very warm, moist air to the east from hot, dry air to the west. Tornado-producing thunderstorms may form as the dryline moves east during the afternoon hours.

Along the front range of the Rocky Mountains, in the Texas panhandle, and in the southern High Plains, thunderstorms frequently form as air near the ground flows "upslope" toward higher terrain. If other favorable conditions exist, these thunderstorms can produce tornadoes.

Tornadoes occasionally accompany tropical storms and hurricanes that move over land. Tornadoes are most common to the right and ahead of the path of the storm center as it comes onshore.

Answer 5

There's a place in the United States called tornado alley, that stretches from North Dakota all the way down to Texas and as far West as the Rockies to the Ohio River,

Answer 6

I do not think that the US has the most tornadoes. They certainly have some big ones. About a week ago the UK had 10 in one day. . I think size for size the UK has more. It never has an F5 or F4 they are usually about F1 or F2. An interesting question and look forward to seeing some more answers.