Hi BL--the Summit County resort spokespeople are saying that they aren't very worried, for whatever that's worth. Keystone and Arapahoe Basin are probably the most concerned, I suspect, as their water comes primarily from the upper Snake River drainage, with minimal storage. They are restricted from bringing the water level in the Snake below a certain level, and they've had problems with that in years past. This year, the water is extremely low already.
As unbelievably low as Lake Dillon is--and it's frightening--remember that none of the snowmaking systems draw any water from that reservoir anyway. A good change in the weather, with some drenching rains, could quickly raise the water levels in the upper reaches of the drainages, where the snowmaking water comes from, and completely change everything very quickly.
We can only hope!