Without fuel, dying of thirst high on a snowy mountainside you have one source of heat that is tragically going to waste, your outgoing breath.
Pack a widemouthed quart bottle full of snow. Poke a deep, wide hole in the middle of the snow. Insulate the bottle. Blow down the hole. Keep the snow packed on the sides in as broad a layer as possible. In 30 minutes or so you will have one cup of liquid water.
Using a couple feet of 3/4" tubing makes routing the air more convenient. Just shove one tube into the bottom of the snow packed insulated bottle. Blow. Or use 2 tubes, with the tubes fitted thru a spare bottle cap. The 2nd tube is to route the expelled air out of your sleeping bag or parka.
