reply to post by LeLeu
During the last ice age most of the free fresh water in the northern hemisphere was locked up in the north American an European ice sheets. Most of
northern siberia was very arid, and I'd imagine that since the free freshwater was locked up in continental ice sheets, the arctic ocean was
relatively ice free.
Without the reflective ice pack the water would absorb more solar radiation, and water holds heat better than land so the ocean would have moderated
the temperature well into coastal plain.
Also rivers moderate micro climates in their area.
Winters would have been harsh, but summer temps could have been in the 40-50 deg. F range as they are now in the same region.
The animal assemblage they reference would have been arctic adapted varieties such as the wooly rhyno, the horses would have had very shaggy coats
like horses found in modern northern climes
What is most important about the Yana river area its here that we find cultural transition from an earlier neanderthal occupation to modern humans,
with the moderns adapting the neanderthal technologies and living techniques.
For those interested in the early occupation of the arctic look to Bluefish cave in Canada.
Bluefish Caves is the name of a Paleoarctic archaeological site composed by a series of small caves located in the Yukon Territory, Canada. The
site represents one of the earliest evidence of human occupation in the North American continent. Remains of Pleistocene mammoth, bison, horse,
caribou and muskoxen, were found in shallow deposits within three limestone cavities located above the Bluefish river
Bluefish Caves is an archaeological site in Yukon, Canada, located 54 km southwest of the Vuntut Gwichin community of Old Crow, from which a
specimen of allegedly human-worked mammoth bone has been radiocarbon dated to 28,000 years before present (y.b.p.).
Bluefish Cave was initially discovered by a fish expedition in 1976.  The initial find of a mammoth bone spear point was made by archaeologist
Jacques Cinq-Mars in 1978-79,  but not radiocarbon dated and published until the early 1990s due to lack of funding. As the Clovis-First theory,
which dominated New World archaeology until recent years, is revered by the archeological establishment, the research of Cinq-Mars that suggests a
date of 28,000 y.b.p. was largely ignored, and he was unable to obtain funding for follow-up research until 2008.  Findings at a site in Chile
dated human existence there back to 12,500 years ago. With the Chile site findings being decreed valid by prominent archeologists, it gave renewed
interest and possible validity in the Bluefish Cave sites.
Recently another team has discovered allegedly human-worked mammoth bone flakes in the Bluefish Caves area, radiocarbon dated to an even earlier
period of 40,000 y.b.p. 
Now ima gonna bang my alternative American settlement drum.
The 40 k year old date for bluefish caves bolsteres the argument for a north American origin for culturaly modern humans.
There are controversial sites in Oklahoma and Mexico that show human occupation
50k years ago.
That's discounting the absurdly old sites of valsequillo and calico hills that have datings in the range of 100-200k years .