Inside Rossi e Volante Bivouac 3778m
On the night of 10th September 2014 there were 13 overnighting although supposed to have room for only 12. The last 2 arrived at around 6.30pm. It was a tight fit and very hot. My son Keith and I made sure we were first away next morning and climbed both Castor 4223m and Pollux 4092m before returning. The second night there were just us plus an Italian pair - and the temperature in the hut was a bracing minus 5 centigrade.
In peak season I'd recommend saving a place very early - or better still taking a tent!