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Ice roads (ice crossings, ice bridges) are frozen, human-made structures on the surface of bays, rivers, lakes, or seas in polar regions. They link dry land, frozen waterways, portages and winter roads, and are usually remade each winter. Ice roads allow temporary transport to areas with no permanent road access. Seen in isolated regions of northern Canada, Alaska's Bush, northern Michigan, northern Scandinavia, Northeast China and Russia, they reduce the cost of materials that otherwise would ship as expensive air freight, and they allow movement of large or heavy objects for which air freight is impractical.
Ice roads differ from winter roads in that they are built primarily across frozen waterways; however, an ice road may in some cases be part of a longer winter road whose path traverses both water and land. Ice roads may be winter substitutes for summer ferry service. Ferry service and an ice crossing may operate yearly at the same time for several weeks.
Because ice roads are flat, devoid of trees, rocks and other obstacles, they have a smooth driving surface. They are largely plowed across frozen lakes, with a short overland portage between the shoreline of one lake and the next. Similar to ice roads, ice runways are common in the polar regions and include the blue ice runways such as Wilkins Runway in Antarctica or lake ice runways like Doris Lake Aerodrome in the Arctic. Ice is used as an emergency landing surface.
In general, these roads are built in areas where construction of year-round roads is expensive due to 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 and winter roads are used where year-round roads are expensive or impractical. When frozen in winter, the waterway crossings can be built up with auger holes to flood and thicken the crossing. Clearing snow (which insulates and warms) makes ice thicker, more quickly. These seasonal links last anywhere from a few weeks to several months before they become impassable.
After an ice road is plowed across a lake, the ice there gets much thicker than the surrounding lake ice, because the snow cover is swept off — exposing the road directly to subfreezing air (temperatures as low as −50 °C (−58 °F)). 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, roads over water present a great danger to anyone using them. Speeds are typically limited to 25 km/h (16 mph) to prevent a truck's weight from causing waves under the surface. These waves can damage the road, or 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 due to variations in temperature.
Use of ice as the main construction material allows unusual construction techniques: to make a ramp to get the road over a step such as the shore of a lake, for example, lake water is pumped out and mixed with snow to make slush, formed into the shape of the ramp, and allowed to quickly freeze in the intense cold. Worn and damaged roads are repaired by flooding with shallow water that freezes into a new surface layer.
The South Pole Traverse (McMurdo-South Pole highway) is approximately 1,400 km (870 mi) long and links the United States' McMurdo Station on the coast to the Amundsen–Scott South Pole Station. It was constructed by leveling snow and filling in crevasses, but is not paved. There are flags to mark the route.
In addition, the United States Antarctic Program maintains two ice roads during the austral summer. One provides access to Pegasus Field located on the Ross Ice Shelf. The ice road between Pegasus Field and McMurdo Station is approximately fourteen miles. The other road provides access to the Ice Runway, which is located on sea ice. The road between the Ice Runway and McMurdo Station varies in length from year to year depending on numerous factors, including ice stability. These roads are critical for the resupply of McMurdo Station, Scott Base, and Amundsen-Scott South Pole Station.
Some of the first ice roads in history were built in the 1930s in northern Canada, for use by caterpillar sleds pulling heavy loads called tractor trains for mines where loads were too heavy for transport by aircraft and the soil too boggy for standard roads when the land was not frozen. Tractor-freighting was eventually phased out in the north and replaced with truck transport over well-maintained ice roads - in the far north, these were first engineered by Al Hamilton of Grimshaw Transport in the 1950s and later perfected by John Denison of Byers Transport in the 1960s, and Robinson's Trucking in the 1980s.
Winter roads and ice roads in Canada are found primarily in northern parts of some provinces, as well as the sparsely-populated northern territories of Yukon, Northwest Territories and Nunavut. In Nunavut, while there are a number of permanent roads within the territory, the Tibbitt to Contwoyto Winter Road, linking Nunavut to Tibbitt Lake in the Northwest Territories, forms the territory's only road access to the rest of North America's road network.
Winter roads may also be found in the sparsely populated northernmost regions of some Canadian provinces. Most communities north of Ontario's Albany River are served by winter roads. Most of these roads in Northwestern Ontario are linked to the Northern Ontario Resource Trail, a permanent gravel road which extends northerly from the end of Highway 599 at Pickle Lake, the northernmost community in the province with year-round highway access. In Northeastern Ontario, some communities are linked to Moosonee, a town that has rail access but no road access to the south.
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 cm (8.7 in) along the entire route. An ice road to Piirissaar Island in Lake Peipus is opened in most years, while colder winters permit opening official ice roads on the Baltic Sea between mainland Estonia and the islands of Hiiumaa, Vormsi, Muhu and Kihnu, between the islands of Saaremaa and Hiiumaa and also between Haapsalu and Noarootsi. As of 2011, the longest ice road in Europe is the 26.5 km route between Rohuküla on the continent and Heltermaa in Hiiumaa. The limitations for ice road traffic include:
Ice road lengths:
The Finnish Road Administration maintains some ice roads during winters. These roads are considered as public roads when they are open. The longest 7 km (4.3 mi) road crosses Lake Pielinen. Ice must be at least 40 cm (16 in) thick before the road may be opened. The following limits apply to ice roads:
On the severest winters ice roads have been privately constructed from the mainland of Finland to the Åland Islands and elsewhere in the Archipelago; using these is unlikely to be within any insurance policy.
Over the Tana river there are usually two ice roads from December to April. These roads have a weight limit of 2 t (2.0 long tons; 2.2 short tons), but few other limitations. There are numerous ice roads over frozen rivers elsewhere in Norway.[specify]
In the northern part of Sweden there are many ice roads. The Swedish Road Administration maintains most of them, but some private ice roads also exist. Ice roads are usually put in when ice thickness exceeds 20 cm (7.9 in). The limitations for ice road traffic normally include:
The longest ice road in Sweden, at 15 km (9.3 mi), is in the Luleå Archipelago, Bothnian Bay, in the northernmost part of the Gulf of Bothnia. It starts in the port of Hindersöstallarna and connects the islands Hindersön, Stor-Brändön, and Långön with the mainland. The ice roads in Luleå are usually open from January to April and have a weight restriction of 2–4 t (2.0–3.9 long tons; 2.2–4.4 short tons).
There are several ice roads across the lake Storsjön. The roads are usually open from January to April and have a weight restriction of 2–4 t (2.0–3.9 long tons; 2.2–4.4 short tons).
The Lena River has an ice road on its surface for hundreds of kilometres during the winter.
There is an ice road in the United States on Lake Superior, linking the city of Bayfield, Wisconsin on the mainland with La Pointe, Wisconsin on Madeline Island. The road is about 2 mi (3.2 km) long and is used for several weeks in the year as replacement for the summer ferry service. When the ice is too thin to allow the construction of the road, but too thick to allow ferry service, a type of hovercraft is used to transport school children from the island to and from the mainland. In Michigan's Straits of Mackinac, seasonal ice roads also connect Mackinac Island and Bois Blanc Island with the mainland.
In Prudhoe Bay in Alaska, there is an ice road over the Arctic Ocean about 25 mi (40 km) long with a maximum speed of 10 mph (16 km/h). It is used a few months during winter to serve an oil field site on the ocean. Another ice road in Alaska is the ice road from Prudhoe Bay, Alaska to Point Thomson, Alaska. The ice road is 68 mi (109 km) long and is on the Beaufort Sea; this ice road is mainly used by semi-trucks to deliver loads to serve the Point Thomson area.
There is a seasonal ice road constructed from the Kuparuk Oil Field to the Alpine oil field, which is roadless in the summer months. This road also connects to the village of Nuiqsut, on the banks of the Colville River. This road is roughly 31 mi (50 km) long and is used to resupply Alpine with critical supplies for operations as well as to transport drilling rigs.
Transport links between Russia and China rely heavily on ice roads which link border Chinese and Russian towns/cities. Because winter temperatures in the Sino-Russian border have average lows of -40 Degrees Celsius, border rivers such as the Amur and Ussuriysk are well frozen by late October/early November. Russian and Chinese border trade solely rely on the ice roads. Notable examples include the ice road linking the Chinese city of Heihe and the Russian city of Blagoveshchensk, and the ice road linking Suifenhe in China and Pogranichny.
The 2008 film Frozen River tells the story of two women who get involved with trafficking illegal immigrants from Canada into the United States by driving them across the frozen St. Lawrence River in their car.
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