| Thompson Pass | |
|---|---|
 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″N 145°43′47″W / 61.12861°N 145.72972°W |
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 weather station in Alaska, recording 500 inches or 13 metres of snow per year on average.[2] In the winter of 1952–1953, 974.1 inches or 25 metres of snow fell—the most ever recorded in one season at one location in Alaska.[3] It is not the most snow ever recorded in one season at one location anywhere in the fifty states as that record belongs to Mount Baker Ski Resort at 1,140 inches or 29 metres in 1998–99.[4] The pass also holds the Alaska record for the most snow in a single day: 62 inches or 1.6 metres fell on December 29, 1955.[3]
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]
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]
- ^ a b Geographic Names Information Service. "Thompson Pass, Alaska", U.S. Geological Survey. Accessed July 2, 2009.
- ^ Desert Research Institute. "State Extremes: Alaska", Western Regional Climate Center. Accessed July 2, 2009.
- ^ a b "Alaska Snowfall and Snow Depth Extremes Table". National Climatic Data Center. National Oceanic and Atmospheric Administration. Retrieved February 9, 2013.
- ^ "National Snowfall and Snow Depth Extremes Table". National Climatic Data Center. National Oceanic and Atmospheric Administration. Retrieved February 9, 2013.
- ^ Bleakley, Geoffrey. "History of the Valdez Trail", U.S. National Park Service. Accessed July 2, 2009.
- ^ Wrangell-St. Elias National Park and Preserve. "The Valdez Trail", U.S. National Park Service. Accessed July 2, 2009.
- ^ Byron Johnson, PE