Jackson Hole - Geography

Geography

The valley is formed by the Teton Range on the western side and the Gros Ventre Range on the eastern side. Grand Teton National Park occupies the north-western part of the valley encompassing much of the Teton Range as well as Jackson Lake. The town of Jackson, Wyoming, is at the southern end. Between them lies, on U.S. Route 26, "Glacier View Turnout" offering a view of Teton Glacier on the north of Grand Teton, and the National Elk Refuge, home of the largest elk herd on earth. The Snake River threads through the entire valley from its headwater in Yellowstone in the north to the mouth of the Snake River Canyon at the southern tip of the valley. Blacktail Butte is a prominent landform rising from the valley floor. The average altitude of the valley is over 6,500 feet (2,000 m).

High altitude and steep mountain slopes on all sides of the valley often cause calm winter nights to be very cold, as radiational cooling from snow-covered ground creates cold air near the surface, which then slides down into the valley due to its higher density. In 1993, this effect during an already severe cold snap plunged the morning low temperature down to −56 °F (−49 °C) in the valley, officially recorded by the National Weather Service. The state record low temperature was also recorded in the valley at Moran at −66 °F (−54 °C) in 1933. Summers are mild.