Thompson Pass

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Thompson Pass
Thompson Pass.jpg
Thompson Pass, as seen in May 2009.
Elevation 2,805 ft (855 m)
Traversed by Richardson Highway, Trans-Alaska Pipeline System
Location Valdez-Cordova Census Area, Alaska, United States
Range Chugach Mountains
Coordinates 61°07′43″N145°43′47″W / 61.12861°N 145.72972°W / 61.12861; -145.72972 Coordinates: 61°07′43″N145°43′47″W / 61.12861°N 145.72972°W / 61.12861; -145.72972

Thompson Pass is a 2,600 foot-high (855 meter-high) gap in the Chugach Mountains northeast of Valdez, Alaska. [1] It is the snowiest place in Alaska, recording 500 inches (1,300 cm) of snow per year on average. [2] In the winter of 19521953, 974.1 inches (2,474 cm) of snow fell—the most ever recorded in one season at one location in Alaska. [3] It is also the most snow ever recorded in one season at one location anywhere in the fifty states. [4] The pass also holds the Alaska record for the most snow in a single day: 62 inches (160 cm) fell on December 29, 1955. [3]

Chugach Mountains

The Chugach Mountains of southern Alaska are the northernmost of the several mountain ranges that make up the Pacific Coast Ranges of the western edge of North America. The range is about 250 miles (402 km) long and 60 miles (97 km) wide, and extends from the Knik and Turnagain Arms of the Cook Inlet on the west to Bering Glacier, Tana Glacier, and the Tana River on the east. It is bounded on the north by the Matanuska, Copper, and Chitina rivers. The highest point of the Chugach Mountains is Mount Marcus Baker, at 13,094 feet (3,991 m), but with an average elevation of 4,006 feet (1,221 m), most of its summits are not especially high. Even so its position along the Gulf of Alaska ensures more snowfall in the Chugach than anywhere else in the world, an annual average of over 1500 cm (800 in).

Valdez, Alaska City in Alaska, United States

Valdez is a city in Valdez-Cordova Census Area in the U.S. state of Alaska. According to the 2010 US Census, the population of the city is 3,976, down from 4,036 in 2000. The city was named in 1790 after the Spanish Navy Minister Antonio Valdés y Fernández Bazán. A former Gold Rush town, it is located at the head of a fjord on the eastern side of Prince William Sound. The port did not flourish until after the road link to Fairbanks was constructed in 1899. It suffered catastrophic damage during the 1964 Alaska earthquake, and is located near the site of the disastrous 1989 Exxon Valdez oil tanker spill. Today it is one of the most important ports in Alaska, a commercial fishing port as well as a freight terminal.


The pass was named in 1899 by U.S. Army captain William Abercrombie "in compliment to Hon. Frank Thomson, of Pennsylvania", but he spelled the name "Thompson" on his sketched map, and that spelling stuck. [1] The pass had been used by Alaska Native Ahtna people for generations prior to Abercrombie's arrival, but he marked and defined a trail through the pass for use by Klondike Gold Rush miners. [5] His route, which became the Valdez-Eagle Trail, later was used by the Washington-Alaska Military Cable and Telegraph System, which strung cables through Thompson Pass. The path through the pass continued to be improved, and automobiles first drove the entire length of the trail in 1913. By that point, it had become the Valdez-Fairbanks Trail, and it was renamed the Richardson Road in 1919. [6]

Klondike Gold Rush 1890s migration

The Klondike Gold Rush was a migration by an estimated 100,000 prospectors to the Klondike region of the Yukon in north-western Canada between 1896 and 1899. Gold was discovered there by local miners on August 16, 1896, and, when news reached Seattle and San Francisco the following year, it triggered a stampede of prospectors. Some became wealthy, but the majority went in vain. It has been immortalized in photographs, books, films, and artifacts.

Fairbanks, Alaska City in Alaska, United States

Fairbanks is a home rule city and the borough seat of the Fairbanks North Star Borough in the U.S. state of Alaska.

Because of heavy snowfall in Thompson Pass, the Richardson Highway was used only in summer.[ citation needed ] Not until 1950, when a freight company foreman demonstrated that the pass could be kept open with snowplows, was the road drivable year-round.[ citation needed ] The trail through the pass remained gravel until 1955, when the Alaska Road Commission (part of the US Department of the Interior) paved it. [7]

Snowplow device for removing snow

A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes. Although this term is often used to refer to vehicles mounting such devices, more accurately they are known as winter service vehicles, especially in areas that regularly receive large amounts of snow every year, or in specific environments such as airfields. In other cases, pickup trucks and front end loaders are outfitted with attachments to fulfill this purpose. Some regions that do not frequently see snow may use graders to remove compacted snow and ice off the streets. Snowplows can also be mounted on rail cars or locomotives to clear railway tracks.

Pipeline construction

In the early 1970s, Thompson Pass was the scene of frantic activity as thousands of workers built a portion of the Trans-Alaska Pipeline System from a camp located nearby.[ citation needed ] Heavy snowfall in the pass slowed work in the winter, but the pipeline was completed by 1977, and oil today flows through the pass on an almost constant basis.[ citation needed ]

Trans-Alaska Pipeline System oil pipeline

The Trans-Alaska Pipeline System (TAPS) includes the trans-Alaska crude-oil pipeline, 11 pump stations, several hundred miles of feeder pipelines, and the Valdez Marine Terminal. TAPS is one of the world's largest pipeline systems. It is commonly called the Alaska pipeline, trans-Alaska pipeline, or Alyeska pipeline,, but those terms technically apply only to the 800 miles (1,287 km) of the pipeline with the diameter of 48 inches (122 cm) that conveys oil from Prudhoe Bay to Valdez, Alaska. The crude oil pipeline is privately owned by the Alyeska Pipeline Service Company.

The Valdez bound Thompson Pass sign, as seen in May 2016. The Valdez bound Thompson Pass sign, as seen in May16..jpg
The Valdez bound Thompson Pass sign, as seen in May 2016.

Because Valdez is the southern terminus of the pipeline and Thompson Pass provides the only overland transportation link to Valdez, the state of Alaska maintains a road service station in the pass to keep it plowed and ice-free year-round. This facility includes Thompson Pass Airport,a short landing strip used by state aircraft which also serves as home to the annual Tailgate Alaska event. The work of keeping the highway through the pass clear is extremely challenging due to weather conditions and was highlighted in the Discovery Channel television special Alaska: Most Extreme .

Discovery Channel American basic cable and satellite television channel

Discovery Channel is an American pay television television network and flagship channel owned by Discovery, Inc., a publicly traded company run by CEO David Zaslav. As of June 2012, Discovery Channel is the third most widely distributed subscription channel in the United States, behind TBS and The Weather Channel; it is available in 409 million households worldwide, through its U.S. flagship channel and its various owned or licensed television channels internationally.


The pass is a popular destination for tourists and adventurers. Heliskiing and snowboarding are popular recreational activities.


Heli-skiing is off-trail, downhill skiing or snowboarding reached by helicopter, instead of a ski lift. In the late 1950s helicopters were used in Alaska and Europe to access remote terrain. In 1965 Hans Gmoser commercialized the activity in Canada by combining lodging, transport and guiding. In Switzerland there are an estimated 15,000 heliskiing flights each year, to 42 landing sites. In 2010 Switzerland's major environmental groups, including the Worldwide Fund for Nature, handed a petition with over 15,000 signatures to the Swiss government, demanding a ban on heliskiing. Heliskiing is banned in Germany and was banned in France in 1984. Austria allows two landing sites.

Snowboarding Recreational activity andWinter Olympic and Paralympic sport

Snowboarding is a recreational activity and Winter Olympic and Paralympic sport that involves descending a snow-covered slope while standing on a snowboard attached to a rider's feet.

Protected areas

Blueberry Lake is situated on the side of a mountain in the Pass, inside a switchback of the highway. Blueberry Lake campsite.jpg
Blueberry Lake is situated on the side of a mountain in the Pass, inside a switchback of the highway.

Blueberry Lake State Recreation Site is a 192 acres (78 ha) park in Thompson Pass. It has a lake with Arctic grayling in it, a campground, and several picnic areas. [8] It has been described as “one of Alaska’s most beautifully situated campgrounds”. [9]

Worthington Glacier State Recreation Site is a 113 acres (46 ha) site with picnic areas, interpretive displays, and trails enabling visitors to approach the glacier. [10]


Thompson Pass has a polar climate with one of the highest snow totals in the world. In spite of its high latitude it retains a mediterranean precipitation pattern, with dry summers, although those are too cool to qualify for dry-summer subarctic.

Climate data for THOMPSON PASS, AK
Average high °F (°C)10.3
Average low °F (°C)−0.7
Average precipitation inches (mm)6.18
Average snowfall inches (cm)61.9
Source: The Western Regional Climate Center [11]

See also

Horse-drawn sleds crossing Thompson Pass in the early years of the 20th Century Color post card. "Winter Trail over Thompson Pass, Alaska." Dog Sled Teams. - NARA - 297822.jpg
Horse-drawn sleds crossing Thompson Pass in the early years of the 20th Century


  1. 1 2 Geographic Names Information Service. "Thompson Pass, Alaska", U.S. Geological Survey. Accessed July 2, 2009.
  2. Desert Research Institute. "State Extremes: Alaska", Western Regional Climate Center. Accessed July 2, 2009.
  3. 1 2 "Alaska Snowfall and Snow Depth Extremes Table". National Climatic Data Center. National Oceanic and Atmospheric Administration. Retrieved February 9, 2013.
  4. "National Snowfall and Snow Depth Extremes Table". National Climatic Data Center. National Oceanic and Atmospheric Administration. Retrieved February 9, 2013.
  5. Bleakley, Geoffrey. "History of the Valdez Trail", U.S. National Park Service. Accessed July 2, 2009.
  6. Wrangell-St. Elias National Park and Preserve. "The Valdez Trail", U.S. National Park Service. Accessed July 2, 2009.
  7. Byron Johnson, PE
  8. Blueberry Lake SRS Alaska Department of Natural Resources
  9. The Milepost 2018 Edition, page 433, Morris Communications ISBN   9781892154378
  10. Worthington Glacier SRS Alaska Department of Natural Resources
  11. "THOMPSON PASS, ALASKA (509146)" . Retrieved May 14, 2016.

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