I have had success traveling in winter in the northwest with:
- -10 or -20 degree SYNTHETIC bag keyword SYNTHETIC Down is useless when wet. Even treated down.
- 10 X 12 heavy duty tarp. you can make many different kinds of shelters with this size tarp. Lean-to, tent, wood-ribbed shelter, burrito.
-Something to insulate you from the ground is key, cardboard, sleeping pad, ect.
-synthetic long underwear is key, usually 2 pair. A lot of people say long underwear is over-rated, it is not.
-*LAYERS* base layer(long underwear), mid layer (Regular clothes), warmth layer (Fleece), Outer layer (WATERPROOF jacket and pants) you can add more or less depending on the weather and temerature
-WOOL socks, a few pair. Make sure you have good boots, alot of people I know wear straight up rubber boots in the winter, with a change of regular shoes.
-Carry a pack cover or poncho for your pack. I line the inside of my pack with a trash bag
-If it rains alot, carry an umbrella. A lot of people bash umbrellas, but they have saved my ass in Eugene and the oregon Coast more than I can count.
-hand warmers are cool, if you can find 'em
-DO NOT wear cotton, cotton is fucking useless
*As far as technique goes:
-try not to camp on snow, unless there is 1+ feet of it to insulate you
-always sleep on a trap or cardboard to insulate you from the ground
-If your body starts telling you that it should really get indoors for a while, do it. listen to your gut.
-Drinking does not make you warmer. Dont drink a shit load and then expect to survive temps under 40 without any kind of shelter/bag
-Eat alot. your body is an organic heater, and it needs to be constantly stocked, the more you are in wet/cold environments.
-If your looking to squat, in the winter there are many abandoned second "Summer" homes. Looks for areas that looks like they are vacation rentals/community. Its pretty obvious whether someone has been in their home recently or not, especially when there is snow.
-Be very mindful of camping under trees in the winter. Snow load breaks limbs, and whole trees, add wind to that and it could be a disaster. ALSO getting under tree when it is raining/sleeting will be wetter and drip more than not being under trees. It you are going to stay under trees in these condition, looks for evergreens, they are better cover.
-that brings another point. Evergreen trees have 'tree wells' when there is alot of snow on the ground, it is the lowest part of the tree that doesnt get alot of snow around the base, creating a 'well'. these are great areas to build a shelter, and the snow will insulate you from cold/wind
-making igloos and snow caves are great. but please, know what you are doing first, those things can collapse in the middle of the night, and you can suffocate.
-Dont let yourself sweat. take off layers if you start to get hot, sweat will kill you, from the inside out.
-Know the signs and symptoms of hypothermia, as well as frostbite first aid
- #1 thing is dont get wet.
Here is a site with a few other tips:
http://wildwoodsurvival.com/survival/winter/index.html