Be sufficiently experienced, fit and equipped for your intended trip. Practice hiking or skiing with a rucksack away from trails and tracks, even if conditions are poor. Your physical and mental fitness, your experience and your equipment determine the sensible distance of a tour.
Leave word of your route
Many cabins, hotels and other lodgings have tour notification boxes in which you may put a written notice of your planned route. In an emergency, the details you give will aid the rescue service.
An old adage advises that you should always be alert to forecasts of bad weather, yet not rely completely on forecasts of good weather.
Regardless of the forecast, you should be prepared for bad weather. Even a fresh breeze (Beaufort Scale 5) combined with sleet or frost can produce frostbite.
Weather forecasts are not sufficiently detailed to forecast local weather in mountain areas. Despite forecasts usually being right, it is difficult to predict when weather will change. So you should heed forecasts in adjoining lowlands as well as in the mountains, and follow weather changes. It can be a good idea to seek advice with the locals.
Be equipped for bad weather and frost
Always take a rucksack and proper mountain gear. Put on more clothing if you see approaching bad weather or if the temperature drops.
A roomy wind- and waterproof anorak, wind- and waterproof trousers, wind- and waterproof mittens and a warm hat or cap are good outer clothing. Put them on before the weather gets too bad. Stand with your back to the wind and help others put on their clothing. Use a survival bag for additional protection.
Learn from the locals
Local people can often tell you about avalanche trails, wind and snow conditions, and the safest routes.
Use a map and compass
Always have and know how to use a map and compass. Before departing, study the map and trace your route to gain a basis for a successful tour.
Follow the map, even when the weather and visibility are good, in order to always know where you are. When visibility deteriorates, it can be difficult to determine your position.
Read the map as you go and take note of points you can recognize. Rely on the compass. Use a transparent, waterproof map case attached to your body so that it cannot blow away. Take bearings between terrain points on the map that can guide you to your goal. Use the compass to stay on a bearing from a known point.
Do not go solo
If you venture out alone, there is nobody to give you first aid or notify a rescue service in an emergency. Yet there is not always safety in numbers. A large party is inadvisable, particularly if its members are unequally experienced. A party never is stronger than its weakest member.
Turn back in time - sensible retreat is no disgrace
If conditions deteriorate so much that you doubt you can attain your goal, turn around and return.
Do not try to defy weather, as others may risk their lives to rescue you. If you change your goal, be sure to notify the people who are expecting you. If you start a tour in windy, uncertain weather, go against the wind's direction. It will then be easier to backtrack if necessary.
Conserve energy and build a snow shelter if necessary
The stronger the wind, the tougher the walking/skiing. Suit your speed to the weakest member of the party and avoid sweating. If you go in single file, turn often to ensure that the others are following, more so in bad weather when it is hard to hear voices.
Remember to eat and drink frequently. Physical activity increases the body's need for liquid intake, even if you do not feel thirsty. Insufficient food and drink lead to lethargy, and you can become discouraged.
Start building a snow shelter before you are exhausted. A few hours are enough to build a snow trench or snow cave. When you have surplus time and energy, practice building a shelter - the experience gained can be valuable. A survival bag can provide emergency shelter.
Learn more about winter safety in the Norwegian mountains through this PDF.