This is not a trivial point.

At Arctic temperatures, inadequately clothed humans die within hours.

The people at Yana were not wearing animal skins thrown carelessly over their shoulders.

The presence of bone needles among the Yana artifacts — some of them among the finest and most carefully made needle-like tools from the Upper Paleolithic — tells us they were making tailored, sewn garments.

Clothing that fit the body closely, that trapped body heat, that could be layered against extreme cold.

The technology of Arctic cold-weather survival was already developed at Yana 31,000 years ago.