A Survival shelter that I can recommend is kind of difficult to explain. I'd have to draw it for you. But it's a round shelter, it's walls are stacked walls, with four poles going up in the center which surrounds the fire pit, Bracing the poles are beams tied around the top of the poles. Now. Put long poles all around on top of the stacked walls for the roof leaving enough room for a smoke hole. Then put slabs of bark or whatever on top of the logs, and gather up a huge amount of leaves and brush and pile it on. It should be twelve feet wide from the inside of the stacked wall to the other inside side. My friends and I made one and has kept us warm whenever we camp out in it in the winter, and cool in summer.
Graphic by March Besse