Hey good luck on your first mulie hunt. I have been hunting these deer all my life, and I'll tell you, this stuff gets under your skin. As for your question, deer do move to lower elevations as snow accumulates up higher. I just read some research that showed about 50% of mule deer in the study area moved from summer range to winter range due to seasonality alone (no significant snow forced them to move). The other half waited until they were forced down lower by snowfall. I have heard that it takes about 12" of snow to make deer move (elk about 18"). Now this is snow that is there for the winter and not an early 12" snow that will melt off in a few days. Where you have migrating deer herds, snow can make a world of difference. I prefer to hunt right at snowline. I believe that generally, the biggest bucks will hang as high as the snow will let them. This is, of course, unless the rut is beginning, in which case all bets are off. I have seen big ol' wiley bruisers wandering residential areas looking for doe love. I hope you have a great hunt. Let me know how it goes. By the way, where you huntin'? I have a third season CO tag in 75/751. I hunted there last year and took a smallish 4-pt. I had a great time.