Did you know?
"Only a thin layer of ice separates a truckload of cargo from lake water as it travels across the Canadian tundra. How are roads engineered and built atop lakes?"
The Freezing Point
The freezing point is defined as the temperature in which a liquid changes to a solid state. For example, the freezing point of water (under standard atmospheric pressure) is 0°C (32°F). This is also known as the ice point...the point at which water turns to ice.
Chances are that you prefer ice with your soda, enjoy ice-skating at a nearby rink or have seen an artist carve a fancy ice sculpture from a solid chunk of ice. Although these are all terrific uses of ice, do you want to know about one of the most amazing feats ever accomplished with ice?
Journey On The Ice Roads
Can you imagine driving a 40-ton (38 metric ton) truck over a lake – not on a bridge, but over just a layer of ice?People do just that in some of the coldest, iciest parts of the world. But the ice they drive on is special ice – safely engineered to hold vehicles carrying heavy loads. To learn more about the history of the roads, where they are located, how they are built, who uses them and why, travel along the ice roads with us now.
North by Northwest
Where Are The Ice Roads?
Traveling over temporary roads made of ice is often necessary in remote areas where there are few permanent roads or no roads at all. They are located in parts of the world where there is plenty of ice and no shortage of cold weather to keep the ice from melting for long periods of time. The Northwest Territories of Canada in North America is located in a polar zone which makes it a perfect place to build ice roads.
The Canadian tundra is one location where there are not many permanent roads. Very few people live in these areas. The land is covered with large lakes in the warmer months. These lakes are covered with ice in the colder months. It would be very expensive to build permanent roads and bridges in these remote areas. Even if they were built, it would be almost impossible to keep them clear of snow and passable in the winter. So, in these northern areas, people cleverly travel over the ice that covers the land much of the year instead of building costly roads which could be used only rarely.
One of the main cities in the Northwest Territories is Yellowknife. Yellowknife is the starting point for many of the ice roads that are built every winter to the outer areas of the Northwest Territories. Wait a minute...built every winter? If you wonder why they must be built every winter you must first know that the ice roads melt away every spring!
Cold As Ice
How Are The Ice Roads Built?
The ice roads are also called winter roads. That's because they simply do not exist during the warmer months of the year. Here's how the building process starts: around mid-November every winter, the temperature drops, the lakes freeze over, the marshy areas turn solid and the land surface is frozen.
The ice roads are built over the lakes and the land between the lakes. Land between lakes is known as portage. Around late December, the ice on a lake is 12” (30 centimeters) thick. At this point, snowplows clear the snow off the ice to make the ice turn thicker, faster. You might think the snow helps the ice get thicker, but the opposite is true. Snow covering the ice layer acts as an insulator. If the snow is plowed off, the ice is directly exposed to subfreezing air. In this area, temperatures drop to lows such as 40° below zero! (The –40° temperature is the only point at which the Farenheit and Celsius scales register the same.)
After the ice is plowed across a lake, the ice gets much thicker than the surrounding lake ice, forming the start of an ice road. During construction, ice thickness is measured every day. One way it is measured is by drilling holes through the ice to measure its depth. Another way to measure its thickness, is by using high-tech ground-penetrating radar to profile (or “read”) the ice sheet. Often maintenance crews use augers to drill through the ice to obtain water to use to improve the thickening process.
Once the ice thickens to 27”- 28” (.7 meters) over the entire road, trucks with very light loads are allowed to cross. Once the ice reaches 41”- 42” (1 meter) thick along the entire road, it is thick enough for a Super B tanker fully loaded with up to 50,000 liters of fuel to drive across. (A Super B is a tractor hauling two tanks of fuel and weighing approximately 42 tons or 38 metric tons.) At this point, ice roads are officially open for the winter season. Depending on the region and seasonal temperatures, ice roads can last anywhere from a few weeks to several months.
Ice roads are usually ready to open in January. Then they are constantly monitored for safety. It is extremely important that all drivers follow the rules of the road for the safety of everyone traveling on the roads. Speed limits are strictly enforced - typically, 15 mph (24 km/h) for loaded trucks and 35 mph (56 km/h) for empty trucks. If a truck travels too fast, the weight of the truck can start waves under the ice next to the lake's surface. A wave under the ice can cause the water to swell up and crack the ice. This is known as a blow-out. A blow-out of the ice can cause a vehicle to partially or completely fall through the ice! Fortunately, this does not happen very often. If a blow-out or cracking does occur, construction crews can repair the ice.
Once temperatures begin to warm in the spring, the ice roads are closed. They are usually closed in early April. When a lake thaws in the spring, the ice under the road is the last to melt. In the summer, traces of the roads can still be seen from overhead in a low-flying plane. This is because you can see bare strips on the lake bottom where the thick ice blocked the sunlight and prevented plants and algae from growing under the ice roads. In this cycle, the roads simply melt away.
Riding The Roads
Who Travels On The Ice Roads?
Dog sleds, automobiles, large trucks (even U-Haul trucks!) travel over the ice roads. But by far, the most frequent travelers on the ice roads are the truckers who supply northern communities and industries with supplies. Communities in remote areas depend on supplies to be trucked in for the winter. Before ice roads were constructed, supplies were brought in by dog sleds or airplanes. Both means of transportation had weight limits, making large, heavy loads either impossible or very expensive to transport. Ice roads now support the transportation of a huge amount of supplies. For example, one ice road - the Tibbitt to Contwoyto Winter Road - ran a record 10,922 loads hauling 331,000 tons (300,300 metric tons) of supplies by trucks in the 73 days it was open for the 2007 winter season. That would be an impossible feat using dog sleds or planes!
The main industry that hauls supplies by truck is the mining industry. Diamond mining in the Northwest Territories is an important industry and Canada now is the third largest supplier of diamonds in the world. To be able to build the mines, supply equipment to the mines, and support the miners who work there, trucks haul large loads of construction equipment, fuel and other necessary supplies. Trucks carry tons of aviation fuel, diesel fuel, oversize construction equipment, thousands of bags of cement and prill (ammonium nitrate), for making explosives, to the mines.
The ice roads are so important to the mines that many of them work together to build the roads, maintain them and manage them. They make sure truckers follow the rules and drive safely. They also control the access to the roads by the truckers. The Tibbitt to Contwoyto Winter Road, is a road which is operated and monitored by a group of several mines. The operation monitors the weight of all the trucks and the cargo they hold, keeps track of when a truck is dispatched and arrives, and sees that the trucks are safely spread out along the routes.
You might think that it is very dangerous to drive these ice roads - especially in a truck hauling very heavy and potentially dangerous cargo. You might even imagine that these trucks sometimes fall through the cracks of the ice. You would be right; occasionally, accidents do happen. But these are very rare events and the safety record of these roads are impressive. The registered truckers (about 700 of them on the Tibbitt to Contwoyto Winter Road in 2007) are professionally trained and well-prepared for winter conditions, and they obey the rules of the road. If they do not, they are not allowed to travel on the ice roads!
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