In the Canadian Arctic, very remote exploration sites, mines and communities depend upon links to the south. They need construction equipment, building materials and fuel, as well as basic survival goods - like food.

The permafrost conditions make gravel roads hard to build and maintain. In mid-winter however, a solid roadbed - capable of supporting heavy trucks - can be constructed by clearing a route across the frozen ground and lakes.

The Tibbitt to Contwoyto winter road (starting at Yellowknife) is one of the world’s longest heavy haul ice roads, covering a distance of 568 km / 353 miles - 87% of which is over frozen lakes! Land portages link the flat frozen bodies of water.

Road construction begins each January using plows, graders, water trucks, dozers, and snow blowers. The road is just used through February and March, but that's enough time to transport up to 8,000 truckloads and almost 250,000 tonnes of freight!

Roads built on lakes are not without dangers (recently a driver was lost when the snowplow he was driving fell through the ice into 30 meters / 100 feet of water).

•  Holes are drilled to check the thickness of the ice. If some extra "paving" is required, the water trucks come out.

•  Roads are plowed extra wide so storms don't block them.

•  Ice under snow is not as strong as exposed ice (snow is a good insulator), so the snow is removed to expose the ice to the cold Arctic air, making the ice on the roadbed stronger and thicker than the ice around it.

•  Speed limits are strictly observed. Ice is flexible - trucks create waves under the ice and if they move too fast, those waves may burst out at the shoreline.