If you are planning a trip to the wilderness or high mountains, make sure that you have sufficient ability, knowledge and adequate equipment to deal with all possible surprises the weather may have in store for you. Make sure that you know where the next refuge is located and how far it is from you.
Sleeping bag. Contrary to widespread belief that warmer is better, a sleeping bag can actually be too warm. Excessive sweating leads to wet clothing and wet sleeping-bag filling (particularly in the case of down). This makes you feel cold, despite the fact that you are expecting a warm sleeping bag.
Iso mats. A good insulating iso mat is just as important as a good sleeping bag. For winter tours, we recommend self-inflating mats of at least 3.8 cm thick.
The weather. Over a five-day period, the weather usually changes by plus/minus 5°C, and in stormy conditions the changes can be far greater. You also get wet, tired and cold if it rains or snows. Lying in your sleeping bag after hiking in the pouring rain reduces cold protection, since the sleeping bag is damp and you are tired. Check out the long-range weather forecast.
Altitude. The night temperature in the valley may be warm, but high in the mountains it is far colder. As a general rule of thumb, expect the temperature to fall by 5°C for every 1000 metres of altitude. The weather in the mountains can also be far more extreme than in the valley.
Even the best sleeping bag cannot replace the following safety precautions:
Take extra clothing with you. Even in summer, we recommend that you carry expedition undergarments with you, in particular a thermal vest with long sleeves and long leggings. A full set weighs just 400 grams and can be used day and night. You can wear it under your normal clothes during the day, and on cold nights you can sleep in it as well. Where possible, wear clothing that effectively transports moisture away from the body (no cotton). Each night, a sleeper loses 3 to 5 decilitres of water in the form of sweat. If this moisture is not transported away from the body, you can soon start to feel cold. If you are expecting sub-zero conditions, take a face mask and bivouac socks with you too. The heat of the sleeping bag can easily be increased: by wearing expedition undergarments, a storm cap and socks.
Make sure you eat enough. If you do not eat enough, your body will produce less heat and you will feel colder. When you are hiking you need a lot of energy to carry you forward. Make sure you drink enough fluids - but avoid alcohol: dehydration reduces the body's ability to produce heat. Liquid intake is therefore very important. Drinking tea or hot chocolate in the evening is better for you than alcohol. Alcohol makes you feel warmer to begin with, but when it wears off you feel the cold even more.
Keep your things dry!Wet clothing and sleeping bags (especially with down) provide far less insulation against the cold than dry items. Try to keep spare clothes and sleeping bags dry. Keep them in a waterproof backpack or plastic bag in your rucksack. Try to keep rain, snow and mud out of the tent. If possible, try to place your sleeping bag away from the tent walls. Open the ventilation flaps in the tent to avoid condensation. Wherever possible, dry the sleeping bag in the open air - for example on the tent.
Wear extra clothing! If you have brought this with you, then you will need it. If you are cold, increase the heat of your sleeping bag by wearing expedition undergarments, a cap, a face mask and socks.
Use a sleeping bag insert. This will improve the heat capacity by around 5°C and protect the sleeping bag from dirt.
Unpack your sleeping bag at once! Remove your sleeping bag from your backpack as soon as you have put up your tent. Shake it to allow the filling to puff out. Exception: if you are wet through, wait until you have changed. Move around to warm up before going to sleep. This boosts the circulation and makes the body generate heat.
Tips when it is getting cold during the night
- Wear additional clothing in the sleeping bag (e.g. socks, expedition underwear and hat).
- Make sure you protect against cold from the ground (best use an insulation mat or if not available use straw, wood, foam or cardboard).
- Make sure you have eaten enough calories before going to sleep.