since they are clocking the extinction as to some 18-24k yrs ago I’m going out on a limb and saying the Flood took care of these bears while the human population was down to a mere handful of people.
That is the PEAK GLACIATION period ~ where even more ice was being created and shorelines were receeding out into the surf by probably 100 ft beyond the earlier Glacial shoreline (worldwide).
The real deal in floods comes with the FIRST MELTDOWN which occurred in Antarctica about 14,500 years ago. If that happened fast, you could have had a gigantic lake form there. With a precipitate collapse of the surrounding Ice wall, the tsunamis could have been a mile high. They would have reached virtually every landmass on Earth ~ check the globe to see how much Southern shoreline is exposed to gigantic Antarctic tsunamis ~ rather sobering. Central Africans, Central and Western Europeans, Central Siberians and people living in the Himalayan Plateau, the New Guinea highlands, Northern Australia, and other places out of the line of this sort of world flood would survive. Fur shur the floodwaters would reach as high as the mountains.
Afterwards the meltdown of the North American ice sheet, and the much smaller Siberian glaciers would have raised sea levels another 100 or so feet.
Eventually that would result in the breakdown of the barrier between the Mediterranean and Black Lakes in near historical times.
You can look up various tables regarding sea levels at the end of the last Ice Age to see that there are different meltdown zones. The two biggest have to be Antarctica and North America. The other meltdowns are of a far lesser scale and impact. That of Antarctica was a world ender. The North American meltdown was far more orderly but destroyed much useful human habitat (alluvial areas near oceans).
The rise of human civilization coincides with a relatively peaceful period in terms of rate of ocean level change. We've had time to adjust and to figure out how to grow our own food and raise our own game.
This is going to end real soon when the ice comes back, the ocean levels drop rapidly, and our alluvial plains rapidly wash away into the ocean depths.
So, tens of thousands of years of a flood to create this process?
I doubt it.
Besides, wasn’t it 40 days/nights?