Don't ask me how I know! But if you are caught in a hailstorm, cold and wet for the night, a G.I. sleeping pad is terrific to insulate you from the ground. And a long-burning candle (lasted a good eight hours) coupled w/a plastic sheet to huddle under and a fleece vest and a thick G.I. knit cap might be just enough to keep you from shivering uncontrollably.
Lifesavers. Literally.
So much for going light. Next time, a good bag, my Svea stove, and a bivy.
In the mountains boy, even in the summer.