When I approached the quinzhee with my co-worker Brett we notices some ice crystals around the entrance. There must have been moist air inside (possibly from people's breath) and it crystalized as it slowly escaped into the colder air.
When we moved inside, we discovered even more amazing ice crystals. Upon closer inspection we could see they had formed on a few strands of human hair that had stuck to the ceiling during the construction process. Each flake was over an inch wide.