Ok so regarding them being at higher elevations in winter, aren't the game generally at lower elevations anyway at that time of year ?
I've been looking at a report today regarding Mule Deer in Chelan County and it seems as if the deer move to lower elevations in the winter for sure (or at least did over the 2 year period that the report was concerning and I'd guess that'd be the case every year), and I know the Elk do all across the State.
I'm struggling to see why Sasquatch would be above the snow line in Winter to be honest.
In Eastern WA the Sasquatch reports go with the game, higher elevations in summer in the main with the lowest elevation reports being in winter.
But that of course is what the humans do too and we all know you need one of them to have a sighting in the first place.