Davey Jackson’s Valley in Winter
April 26, 2021
Photographer: Ray Boren
Summary Author: Ray Boren
It is said that trader and fur trapper Davey Jackson (David Edward Jackson, 1788-1837) spent the winter of 1829 on the shores of a big lake in what is now northwestern Wyoming. If so, he witnessed firsthand both the grandeur and bitter cold of the season at the lake, as well as in the valley now bearing his name (Jackson Lake and Jackson Hole, not to mention the resort community of Jackson), in what was to become, a century later, Grand Teton National Park.
For mountain men of the early 19th century, a hole was a high valley surrounded by mountains, and that definition certainly fits Jackson Hole. It is bracketed by two striking, French-named mountain chains, both trending north and south. The picturesque, serrated peaks of the Teton Range soar to the valley’s west, as shown in the first photograph here, taken on March 2, 2021. On the valley’s east is the Gros Ventre Range, whose often gentler, forested lower slopes rise beyond a vintage farmstead in a second photo, taken the same day.
The Tetons are considered to be the youngest mountain range in the Rocky Mountains, as they began rising 6 to 9 million years ago along the Teton Fault, even as the fault’s east block — Jackson Hole — began dropping, creating a dramatic elevation difference today of up to 7,000 feet (2,134 m) between the highest summits, such as the Grand Teton, elevation 13,775 feet (4,199 m), and the valley floor (Jackson: 6,237 feet/1901 m). As with other components of the Rocky Mountains, the Gros Ventre Range (pronounced Grow-vont) to the east traces its ancestral beginnings to the Laramide Orogeny about 50 million years ago.
Jackson Hole has long, cold winters, stretching from early November through April, with a chance of frost in any month, the National Park Service notes. In winter, the high valley becomes a virtual ice box, especially at night. With already-frigid air trapped in place by the steep bordering mountains, temperatures at the valley’s snow-covered floor can plunge dramatically. According to the U.S. Weather Service, the average January high in Moose, Wyoming, for instance — Grand Teton National Park’s headquarters — is 26 degrees Fahrenheit (3 degrees Celsius), while the average low is 1 degree Fahrenheit (-17 degrees Celsius), with temperatures plunging well below that — into the -50s and -60s — during severe cold snaps.