I read all about quinzee building last Winter and gave it a try in my backyard. We had gotten about 10" or so of good "snowball" snow, on top of 4-5" of older stuff w/a thin crust. I went out in the backyard and cleared a circle maybe 15-18' in diameter, and then started filling it in from the center. I'd throw a shovelful on top, then another, over and over. Eventually I ended up with a mound maybe 8-9' high and 15-18' in diameter. The waiting period is called sintering - I waited maybe 90 minutes or so.
I decided on an entrance side, headed downhill, as my yard slopes, and started digging. Once I got to where my head and torso were in my hole I started getting pretty freaked out. I mean, I had nine feet of snow over my head.....it was weird. I eventually had my fiancee come out and watch me as I was too afraid of having it collapse on me. While I knew this wasn't rational, that it wouldn't, couldn't come down on me, it was an unsettling feeling.
I had poked sticks that were 18" or so long into every side of my pile of snow. It looked like an albino hedgehog. As I dug out I would keep a close watch for sticks, and used them to guide my interior walls. I eventually ended up with a living space large enough to accomodate 2 large adults and their gear. You couldn't stand, but you could sit or kneel comfortably. I used a candle to glaze the interior, poked a hole in the roof for ventilation, and added an entrance tunnel of sorts.
It was a really cool thing to do, but I got hot as hell. While shovelling, while digging, sweating was inevitable. The only way I'd rely on one while in the woods would be if I had another shelter nearby with dry clothes, and optimally, a nice fire. It was very quiet - we had a nasty storm that night with 20-30mph winds and you could barely hear it inside, if at all. Warm too. It's said that it can be -40 out and a quinzee will stay close to 30F. If you have even a tiny bit of kid in you make one - they're a helluva lot of fun.