How tornadoes form and why they are so common in the US

There are more tornadoes in the US than anywhere else on Earth. How do they form? This is in part because of the geography of the US. (AP video/Laura Bargfeld; Production/Shelby Lum; Animation/Eva Malek). Subscribe: http://smarturl.it/AssociatedPress Read more: https://apnews.com​ This video may be available for archive licensing via https://newsroom.ap.org/home