For vast majority of the year, the only way to reach remote but lucrative gold and diamond mines in Canada's northwest is by air. But every winter, something crazy happens. A 370-mile long motorway is built almost entirely on ice—ice strong enough for 70-tonne trucks laden with fuel and supplies.
The Tibbitt to Contwoyto road is the longest heavy haul ice road in the world. In warm weather, the region is an impassable maze of lakes. But when it gets unbearably cold, sheer human ingenuity and perseverance makes the land traversable.
NASA's Earth Observatory recently released a satellite view of the road, which piqued our interest in how it's built. Each January, Nuna Logistics sends Hagglund amphibious track vehicles over the ice. The vehicles, which don't sink if the ice breaks, are equipped with radar for measuring ice thickness and light plows. Once the insulating layer of snow is plowed away, the exposed ice grows even thicker. Additional ploughs, water trucks, and snow blowers strengthen the road and keep it clear of snow. In Popular Mechanics, Jeff Wise writes about workers who have to "struggle through 20-hour nights and windchills that dip to 70 below [-57 Celsius -- Ed]." It is dangerous work. Ploughs have fallen through the ice along with their drivers.
But by February, the ice becomes as thick as 40 inches—thick enough support heavy trucks. Strict speed limits are enforced to keep the ice from breaking. By April, the ice is too thin and the roads are closed.
But the roads don't completely disappear with warm weather. The thick ice of the motorway is the last to melt. Even in the summer, their ghostly imprints are visible as a barren strips across the lake bottoms. The road's ice keeps sunlight from reaching the lake, so plants cannot grow underneath. Like the concrete motorways we build, these ice motorways leave scars in the ground. [NASA, Popular Mechanics]
Images: NASA Earth Observatory