>>220092Hey OP.
The coldest I've slept out in is several days at -45C to -50C in a row. Interior Alaska... pretty cold, I guess....!
Even at -10C nights can be cold! When you're trying to sleep everything feels so much colder than when you're out and about during the day, moving around to keep warm.
If you have a good source of snow, and have a bit of time (a day to set up), making a quinzee (snow shelter) can be incredibly warm. Essentially you make a giant snow pile and leave it for a few hours (the longer the better). The snow compacts under its own weight and changes form slightly. You then return to the pile and dig a small entrance tunnel and then carve out the inside. Snow is an excellent insulator, and so you'll stay warm.
As far as the tarp - honestly, it'll be just as good as most of the tents out there. When I'm winter camping I pile snow all around the base of my tent and as far up the sides as I can manage. This really helps to keep the heat in, and any airflow gaps around the skirt of the tent are plugged up.
Siting where you sleep is important - go somewhere with as much wind protection as possible. Build walls, or dig trenches with snow if you can.
Your worst cold will be coming from the ground - so you'll need a good sleeping mat. Bring lots of blankets - they're cheap and I'm sure you have lots laying around.
Fire is good and can save your ass. Try not to get wet. If you're wet you can get into trouble.
I love winter camping, but it can also be a total bitch. There's nothing quite like cramming your feet into frozen solid boots after a long cold night....
If you're really fucked you can pack up in the middle of the night and hike out - you'll stay warm this way -- of course this works provided you're within reach of somewhere and aren't going to get lost and die during the night.
Have you considered finding a used or cheap duvet? Basically a giant down sleeping bag that usually sits on your parents bed....
