From Robert L. Willett's Russian Sideshow,
...men were supplied with adequate cold weather gear before they left California...the staple garment for the outdoors was sheepskin-lined greatcoat...they wore woolen uniforms topped off with fur hats, with lumber men's socks in place of leggings...They were also issued parkas, shoe packs, heavyolive-drab underwear, and fur mittens.
While the clothing was surely adequate for cold weather, the extreme cold still had its effects. Willett describes two particularly related effects, frayed tempers and drinking. In terms of drinking the Americans got their hands on Russian vodka, something presumably none of them had tried before. Willett quotes a particularly desrciptive account of the vodka drinking in Siberia,
It's qualities are varied; it's virtues many. It has the appearance of oily water and the effects of a young volcano.