Tornado Alley (PROG)

[DesertDrifter]

That is a theory that has been around for a long time, and is still the leading theory, although it may indeed overlap to a degree with a newer one that has many skeptics and is not yet accepted by mainstream scientists-- that an abrupt climate shift caused the extirpation of the Clovis culture and many of the Pleistocene megafauna like woolly mammoths.

The Younger Dryas impact hypothesis contends that an extraterrestrial object exploded over North America at 12.9 ka, initiating the Younger Dryas cold event, the extinction of many North American megafauna, and the demise of the Clovis archeological culture.

https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis

It is an area of unsettled science with many data points and many interpretations. The abrupt climate shift is known, but the reasons why are in dispute. The one that posits that when the continental glaciers melted rapidly, so much fresh water drained into the north atlantic that it interrupted the gulf stream for awhile which had dramatic climate effects seems to fit some scenarios. But extinctions of the megafauna didn't all occur at the same time around the globe. South america lagged almost 400 years behind north america in mammoth extinction.
Siberia also lagged behind. Also, on islands some persisted for a long time. That kind of tips it to humans as a factor.
Then one adds in that Australia had their extinction event 30,000 years before the Younger Dryas... ostensibly because it was colonized by expanding populations of humans much earlier than the americas.