Hiking the Crack Trail in Killarney Provincial Park.
A quick bivy on the mountain to survive the night. Doesn't look like much but the sleeping bag is rated for -30C.
Important Tip: You absolutely need enough insulation from the ground or you'll suck up that coldness all night. A layer of insulation below you is just as important as a layer above you. My winter rule is always use at least 2 sleeping pads or a combination of sleeping pad/thermal blanket. I was perfectly warm that night. The only way you figure this stuff out is by trying it out. Every person is different and what works for one, may not work for you. People with bad circulation have a hard time with winter camping.
The Crack. (horrible picture of it.. can barely see it)