If you are: A) out in the woods, and B) there's snow, then it's easy: Find a pine tree and dig out the snow around the base of the trunk. Use extra pine bows to line the floor. Build up the walls with snow and more branches.
If there's not a pine tree, you could use a large boulder or fence for one wall.
If there's no snow, could you sleep in your car, or perhaps bring a tee-pee along?



