What were the effects of the most recent Ice Age on Yellowstone National Park?

I saw the Nature broadcast last night (12-23-2007), entitled

Christmas in Yellowstone

then I came up with this question today.

I wonder if the glaciers ever made it to that part of the country(?) and did they change the geothermic nature of the
area by putting pressure on the crust, etc.?
2 answers 2