They are working in eastern Oregon.
Think Great Basin rather than Pacific Northwest.
14,500 to 14,000 years B.P., the ice-sheet surface sloped from about altitude 1,000 meters at the international boundary to between 0 and 300 meters at the ice terminus on the continental shelf and in the southern Puget lowland.
It would have been like Siberia in the Great Basin
Not many people realize that the world's ugliest desert aka Mojave/Great Basin, extends all the way up into British Columbia. As an added bonus, I do believe it gets most of its moisture from snow (but still low enough precipitation to qualify as a desert) - a first amongst the world's deserts.
Nothing is more depressing than leaving the upper Sonora and entering the Mojave as you drive north/westward from southern Arizona towards Calif.