It's -15 C. on a dark windy winter evening. Your snowmobile is broke down, Everyone else has gone down the mountain and it's too far to walk. Chances are no one will find you until the next morning at the earliest. What to do? Looks like a long chilly night.

Wind and cold are your enemy. But snow is your friend. If you know how to build an emergency snow shelter, you can keep warm enough overnight to survive blowing snow and very cold winds all the way down to -30 C.

Snow is good insulation. On a cold -30 C day, if you dig under deep snow, you'll find that the ground is not frozen but close to 1 degree C, unless it froze before the snowfall. Snow is a great building material if you know its secrets. A snow shelter can also be dangerous if it is not constructed properly - so you must understand its limitations. For instance, never build or occupy a snow shelter in temperatures above 0 degrees C.

Let's build a snow shelter, also known as a Quinzhee to the Inuit in the Northwest Territories. Every northerner should know how to build a snow shelter. It may save your life. And it's a fun thing to learn to do on a winter day. Children must always be supervised around a snow shelter.

You will need a shovel or something like it to move snow. Avalanche shovels are ideal. A candle or flashlight will come in handy for light. You also should have a dry set of clothes to change into after you build your shelter. It's hard work and easy to become wet from sweat. Pace yourself so that you do not get too wet. If you start to sweat, remove layers of clothes or stop for a break. Keep dry to stay warm.