Deep snow will definately effect their eating patterns. Would you rather dig through 18 inches of snow to find a frozen acorn or graze on the honeysuckle above the snowline? (example only)

Find the new food sources and set up nearby.

Also - are you still wearing your brown camo? This is an excellent time to really vanish into the scenery by wearing all white! I wear a white tyvek suit like painters wear. They are cheap and fairly waterproof. Finish it off with the white hood and boots and you are invisible my friend!