Recent posts mention the polar regions and deserts as extremes in survival. This is natural,we can quickly freeze in one and die of thirst in the other.What is poorly understood, you can do both in each environment. People tend to dehydrate quickly in cold climes. Remember, the general definition of desert is LACK OF WATER. Snowfields are not humid and are subject to high winds. The frozen water underfoot does you no good unless utilised ! The human psyche tends to become introverted and lethargic sitting in a snow shelter, bundled in a mummy bag. We quickly learned ( arctic survival school) to brew something hot after securing fire and shelter. Another trick is to drink varying amounts of water before sleep. People waking during the night to relieve themselves have a chance to look around, check any signal fires, ill companions etc.