Dehydration in the cold

In the cold you lose water without noticing: cold air is dry and you humidify it with every breath, you sweat under your clothes, you urinate more, and thirst decreases. Also, water freezes and is hard to get. Dehydration increases the risk of hypothermia and frostbite.

• Drink on a schedule, do not wait until you are thirsty. Check the color of your urine: it should be clear.
• Melt snow or ice before drinking it. Eating snow cools the body and uses up the energy you need to stay warm. If you melt snow in a pot, put a little water in the bottom first so the pot does not scorch.
• Ice gives more water than snow for the same volume and takes less fuel to melt.
• Purify meltwater just like any other water (chapter 3).
• Store water where it will not freeze: inside your jacket, bottles upside down (ice forms at the top first), wrapped in clothing inside the sleeping bag.
• Warm, sweet drinks provide water and energy. Avoid alcohol: it gives a sensation of warmth but makes you lose heat faster.