Our weather will be below zero in the next few days, and warming up to 15 deg by the time I am in the field. The only tools I will have are a folding knife, and a contractor trash bag. I will carry a gortex bivy and bag as a back up.
We will have one good fire going all night long away from the shelter.
The ground is frozen solid. I will have access to snow, leaves, grass, and some bark. Very few conifers. I carry a messenger bag with me at all times and I want to test living with it alone for 2 days.
I am thinking build up a large bed to get me off the ground and fill the contractor bag with insulation.
Depending on the material I may try a fire in/near the shelter.
Anyhow thanks for the tips I will post an AAR after.
Sounds like fun, but if this is your first attempt at survival shelter building, given the conditions you describe I would suggest having more of a back up plan than a bivy / bag (hot hands , tarp, space blanket, tent, that type of thing). Probably wouldn't need it but if you did, you'd really need it.
If conditions deteriorate dramatically, you may not have the luxury of first time mistakes...we all make them that's how we learn.
Give yourself a cushion to make the lesson less painful.
The rest of the gang here would probably tell me to chill out and quit worrying ("you sound like my mother").