Wind map of the world.
You seem like someone who understands these things so I'm just gonna go ahead and ask you. What is it exactly that makes places like tornado alley in the states be so prone to these weather conditions? Is it purely the landscape or is it a combination of that and how the air mixes in that particular area? I'm pretty sure I learned about it a bit in school, but I am having a particularly difficult time remembering it at all..
Be sure you can find on the internet plenty of explanations like:
American weather specialists may be able to tell you more about it here.