Tornado Alley covers a portion of the mid-USA and has a ton of tornadoes in spring and summer, which most of them are rated at least an EF2. About 50 to 100 years after people, the entire area would be empty of plant life.
100 Years after People: Tornadoes have destroyed almost everything in the rural area around Tornado Alley. These winds give a whole new reason to the book Gone with the Wind.
10,000 Years after People: Tornado Alley has extended to the entire mid-USA. Hardly any trace of humans remain. Texas is now hammered by the strongest of all tornadoes, an EF5. It hits what was Houston. But the City Hall refuses to collapse. The territory for tornadoes is now the entire mid-USA.