MEMPHIS, Tenn. (WMC) -The US gets approximately four times as many tornadoes than the rest of the world combined! Research found that when you put countries outside the US altogether, they only saw about two to three hundred tornadoes per year. Compared to over 1,200 that touch down in the US annually. Canada, comes in 2nd place but only gets about 100 twisters per year according to research.
The US sees more thanks to our geography and having the right ingredients come together to make a tornado in the first place. In order for a tornado to form, you need warm humid and unstable air near the ground and cold air higher up in the atmosphere. The warm and cold air need to be in contact while moving at different speeds and directions. The bigger the contrast of airmasses the better for instability. We know that in the Mid-South these ingredients can come together and quickly.
The reason why this comes together is because we get the warm air from the Gulf and the cooler air from the West aloft, the temperature and moisture profiles are right for thunderstorm formation.
This helps explain why the globe’s middle latitudes, between about 30° and 50° North or South, have the most favorable environment for tornado formation. In the mid-lattitudes polar air can meet up with warm subtropical air and often flows at different speeds and directions wihich can cause rotation within a storm. The Gulf of Mexico is actually the warmest body of water on earth at its latitude, so lots of warm air to fuel storms.
When the two opposing winds come together, they can create a vortex of wind that spins horizontally. As the warm air rises, it tilts the tube vertical to form a rotating storm called a supercell. Only about 20% of supercells produce tornadoes.
Bangladesh,only get 6 twisters and year. Warm, humid air from the warm Bay of Bengal waters travels north and can come in contact with the cool winds blowing southeast out of the Himalayan Mountains. The deadliest tornado happened in Bangladesh and killed 1300 people in 1989!
Tornadoes only strike the same spot once every 1,200-1,500 years, on average. Tornado winds can reach as high as 250 mph.