@AGR: The issue is that being in a National Park, I can't really cut down anything, nor can I make a fire
Had I been in a forest where I can cut branches, that would've definitely been a good way.
I should've mentionned though that I'm in a group of 11 people. We do have a cabin, but with sleeping space for 6. In case of emergency, I could always sleep on the table or something inside.... or convince one of the ladies to let me sleep with her
@Frogfish: I do know I will have more than enough snow, since the beginning of the season there has been about 4 meters of snowfall in that area.
And please keep us updated about your Iceland trip, that's in my short/mid-term todo list so other people's experiences will definitely help me plan my own
As it was fairly cold yesterday (about -20 celcius), I decided to make a test in my backyard. I dug a hole in which I could crawl that covered me up to my shoulders; as I hadn't let the snow settle, I didn't want to risk having anything over my head. I slept with the 3 pieces of the MSS and nothing but my (merino) underwear. I threw my L7 top/pants under me for additional insulation from the snow (I did not use a mattress) and to keep them warm. Other than cold feet, it was fairly comfortable. That should be easy to solve with a bottle of warm water at the bottom of my sleeping bag. I kept my boots warm by putting a Nalgene bottle of warm water inside them.
The biggest issue I had, and I'm hoping someone has ideas on that: snow. Light wind kept blowing snow in my face, and if it was a stronger wind... I'm pretty sure it could've filled the exposed part of the trench (aka my face) overnight.