Actually, in the process, we ended up building two conjoined quinzees, connected by a tunnel. That kept the second quinzee further removed from the light coming in the entrance. With it's floor scraped down to the lake ice, and a corresponding patch of ice exposed on the south side of the quinzee, the sunlight shone up through the floor in a pale green light!
We had a terrific time out at Camp Koinonia the other weekend. The weather was perfect for playing outside all day. We had clear sunny skies, almost no wind, and temperatures of about -10°C. Beautiful!