In reply to JackM92:
Scale, avalanche risk from above and on the walk in (which is not inconsiderable), susceptability to changes in temperature and attendant collapse. All good clean type 2-3 fun.
Put it this way, I never even got there - we stopped at the summer hotel (which is closed for the winter). The booming and roaring from the hills in the cloud all around was fearsome. We dumped our packs, and went for a light footed foray further up the path. Then there was a huge roar that kept on getting bigger and bigger. We ran for the shelter of the hotel and shortly thereafter were 'whumped' by shattered snowflakes spewed out by the unseen monster. We fled as fast as we could and went skiing, which gave great views of the Cirque when the cloud cleared. It also confirmed that we were not going to go anywhere near the place on that trip.
The cirque du Troumousse was also exciting, but not that exciting. The six inches of snow that fell swiftly while we did a route added to the excitement, especially as it rapidly filled useful parts of the lower couloir (like the stances) to a depth of five to six feet. If it had not stopped once we got back to the car, we'd probably still be there, as once the snow stopped the owner of the auberge opened up his garage and started up an ancient Massey Ferguson tractor fitted with a snow plough. We followed him for fifteen miles and about two hours.
Troumousse has a large summer refuge with a winter establishment near by.