Question #a6a30

1 Answer
Jan 8, 2015

The location where nearly 75% of the world's approx. 1,200 annually reported tornadoes occur is the USA.

Tornadoes fare best in flat plains and most commonly occur during the month of May.

A region of the USA extending to about 2,000 miles north of the Gulf of Mexico called "The Great Plains" or "Tornado Alley" is where most of the US tornadoes occur.

Though there are no meteorological boundary lines for Tornado Alley, it traditionally comprises swaths of five US states: Kansas, Oklahoma, Nebraska, South Dakota, and Texas. Texas gets the most tornadoes of any US state.

Some research suggests that the northern reaches of Tornado Alley, extending into Canada, have been experiencing stronger tornado activity in recent years.

Tornadoes are usually a result of conditions when a thunderstorm with a spiraling updraft, called a supercell, brings cold air over a warm area; the ground temperature and air close to the ground are warm or hot while atmospheric air is cold.

The cold air falls and the hot air rises. Not always but sometimes this causes a central column of air to fall while, in equal opposition, air from ground level rises in a tubular fashion, surrounding it.

If the supercell's temperature is far from equilibrium with the ground, then the air rising in the rotating updraft, and whatever debris goes with it, can become a tornado funnel.

A tornado is most likely to formulate:

#*#During a supercell thunderstorm

#*#During the month of May

#*#Between the ground and the stratosphere

#*#In the USA, and as far north as Ontario, Canada

#*#Within the region known as Tornado Alley

#*#On a warm or hot flat plain

#*#Most commony in Texas

There is no more specific a location.