You can be sure that when you head into Montana, you'll be hard pressed to find anything small. That is, except for two couloirs right off of the Lone Peak Tram called Big and Little Couloirs. The Big Couloir is about 45 degrees and 2,000 feet in length and is for expert skiers only, as stated on the tram before you can load. Before you can even enter the chute, you'll be checked for the proper equipment as well (shovel, probe, beacon) as many consider this a no-fall zone. Oh, and bring some water and you're common sense. Lone Peak is at 11,655 feet high. Just enough for the lack of oxygen to deplete your brain functions.
To check out some videos of people skiing the Big Couloir, Click Here and Here.