Ice road
From Wikipedia, the free encyclopedia
 |
The examples and perspective in this article or section may not represent a worldwide view of the subject. Please improve this article or discuss the issue on the talk page. |
 |
It has been suggested that this article or section be merged with winter road. (Discuss) |
Ice roads or ice crossings (which are sometimes referred to as ice bridges), are frozen man-made structures formed on the surface of bays, inlets, rivers, lakes or seas, and are linked from frozen waterway to frozen waterway by overland portages, or winter roads, that are, usually, consistently used from year to year. An ice bridge is a structure which is typically formed during glaciation, and may be related to a significant migration of prehistoric peoples. Ice roads are annual winter-season occurrences that facilitate transportation to and from northern areas which have no permanent road access. Most commonly seen in isolated regions of Northern Canada and Alaska's bush, they are used to help reduce the cost of goods and materials that are normally shipped as air freight.
Contents |
[edit] Ice road
Ice bridges are generally annual winter season formations which provide transportation access to and from communities, mineral deposits, and energy sources that have no permanent road access. They are best known for their role in the transportation system of in isolated regions in Canada's north, primarily because of documentaries and TV series such as Ice Road Truckers.
Ice crossing may be winter season surrogates for the summer ferry service. At the ice crossing of the Mackenzie River near Fort Providence, Northwest Territories both the ferry service and the ice crossing operate at the same time for several weeks of the year.
In general, ice roads and winter roads are used in areas where construction of year-round roads is expensive or impractical. When frozen in winter, the waterway crossings can be built up with a system of auger holes to flood and thicken the crossing. Depending on the region, these seasonal links last anywhere from a few weeks to several months before they become impassable.
Ice roads and winter roads play a crucial role in the transportation of goods to communities without permanent road access. In many of these communities, air transportation is used at other times of the year to bring in goods including food and supplies, but this can be prohibitively costly for bulky goods such as building supplies and heavy equipment.
In general, these roads occur (often with human assistance) in areas where construction of year-round roads is expensive due to the presence of boggy muskeg land. When frozen in winter, these obstacles are easier to cross. Ice roads such as the stretch between Inuvik and Tuktoyaktuk, Northwest Territories, Canada provide an almost level driving surface with few detours several months of the year.
Ice roads are different from winter roads in that they are intentionally built primarily across frozen waterways. Because these are comparatively flat, devoid of trees, rocks and other obstacles, the lakes are easier to clear a path across than bare land, and they can provide a smoother driving surface. The roads built from Yellowknife to Port Radium by John Denison, an early pioneer of ice roads in the Canadian Arctic 1950s-1970s, were almost entirely plowed across frozen lakes, with a short overland portage between the shoreline of one lake and the beginning of the next.
After an ice road is plowed across a lake, the ice there gets much thicker than the surrounding lake ice, because the snow cover has been swept off—exposing the road directly to subfreezing air with temperatures as low as −60 °F (−51 °C). When a lake thaws in the spring, the ice under the road is the last to melt, and in the summer, traces of the roads can still be seen from overhead in a bush plane, as bare strips remain on the lake floor where the ice blocked light and prevented plants and algae from growing.
While easier to drive across in the winter than land, frozen lakes still present a great danger to truckers hauling cargo across. Speeds are generally limited to 15 miles per hour (24 km/h) to prevent the weight of a truck from starting waves under the lake surface, which can dislodge the ice from the shoreline and create a hazard. Another hazard on large lakes is the pressure ridge, a break in the ice created by the expansion and contraction of the surface ice over time due to heat.
The roads are normally the domain of large trucks, an example of which would be the tractor-trailer unit, although lighter automobiles, such as pickup trucks, are occasionally seen, as are snowmobiles.
[edit] Ice roads in Europe
[edit] Estonia
The Estonian Road Administration is responsible for managing ice roads in winter. An ice road may be opened when ice thickness is at least 22 centimetres (8.7 in) along the entire route. Ice roads are mostly used between mainland Estonia and islands off the west coast, like Vormsi, Hiiumaa and Saaremaa. The limitations for ice road traffic include:
- Weight limit depending on conditions, mostly 2 tonnes (2.0 L/T/2.2 S/T) to 2.5 t (2.5 L/T/2.8 S/T)
- Minimal distance between vehicles travelling in the same direction must be at least 250 metres (820 ft)
- Recommended travelling speeds are under 25 km/h (16 mph) or between 40 km/h (25 mph) and 70 km/h (43 mph) 40-70 km/h (25-45 mph). It is advised to avoid the range of 25 km/h (16 mph) and 40 km/h (25 mph) due to danger of creating resonance in the ice layer.
- Seat belts must not be fastened due to danger of drowning in case of ice breakage
- The vehicle must not be stopped
- Vehicles are allowed to enter the ice road in 3-minute intervals
- Ice roads may only be used in daylight
[edit] Finland
The Finnish Road Administration maintains some ice roads during winters. These roads are considered as public roads when they are open. Ice must be at least 40 cm (16 in) thick before the road may be opened.
Following limits apply to ice roads:
- Weight limit 3 t (3.0 L/T/3.3 S/T) (may be raised if ice is thick enough)
- Speed limit 50 km/h (31 mph)
- Minimum space of 50 m (160 ft) between cars traveling in the same direction
[edit] Norway
Over the Tana river there are usually two iceroads from December to April. These roads have a weight limit of two tonnes, but few other limitations. There are numerous ice roads over frozen rivers elsewhere in Norway.
[edit] Ice Runways
Ice runways are common in the Antartic regions for example the Blue ice runway.They are believed to be dangerous but is really safe for airplanes to land on.
[edit] See also
- Road of Life - Ice road across the frozen Lake Ladoga in Russia, which provided the only access to the besieged city of Leningrad in the winter months during World War II
- Tibbitt to Contwoyto Winter Road
- List of Northwest Territories highways
- Highways in Nunavut
[edit] References
[edit] External links
- Government of NWT Department of Transportation - Ice Roads / Ice Bridges / Winter Roads
- Government of NWT Highway Condition Reports
- Building Canada's Epic Ice Road, Popular Mechanics article.
|
||||||||||||||||||||||||
