The Effects of Cold when Walking and Hiking
Exposure to wet, cold conditions coupled with exhaustion can lead to the onset of hypothermia.
This is a condition which arises when the body core is cooled. However, cold alone rarely kills. Instead it is the combination of exhaustion, cold, anxiety and mental stress which can be lethal.
The key factors in avoidance are:
Equipment and Clothing
Waterproof (and therefore windproof) clothing is absolutely essential whether this is worn or carried. It's worthwhile putting on even over other wet clothing as it reduces the wind-chill/evaporation effect.
Remember also to cover the head, hands and lower body well.
Layering of inner clothes is important. This enables you to adjust clothing to work load so avoiding excessive sweating.
For more information on clothing - see Hill Skills > What to Wear > Clothing
Food and Water
Should be consumed before and during the expedition. Eat and drink small amounts frequently. For more information on food - see Hill Skills > What to Take > Nutrition
Over estimation of fitness accompanied by under-estimation of time are the common causes of difficulty. It's important to train and build-up over a period of time to more challenging trips. Regulate the pace carefully during the course of the day.
A minimum of emergency food and equipment should be carried by the party especially in the winter time. Each member of the party should have a survival bag.
For high level winter walks a lightweight bivouac tent to accommodate the whole party is desirable. Excessively heavy loads should be avoided. For more information on equipment - see Hill Skills > What to Take > Essentials
Seek shelter or turn back in good time. It's crucial to preserve a reserve of energy in severe conditions. The mountains will still be there on another day - make sure you can be.