High Wind — Upper Green River Basin Foothills, Wyoming

2020-09-07 to 2020-09-08 · Upper Green River Basin Foothills, Wyoming

Event narrative

The Sublette County Emergency Manager reported dozens of trees downed throughout the area. A messaging sign was blown down east of Pinedale, Wyoming. The sign was rated to withstand 82 mph wind gusts.

Wider weather episode

An unusually cold air mass dropped southward behind a cold front that moved across Wyoming. The front combined with ample moisture as well as strong mid and upper levels winds to bring an historic early season storm to much of western and central Wyoming. Many areas East of the Continental Divide, especially in the higher elevations and adjacent foothills, saw large amounts of snow. The highest amounts fell in the Wind River Range and Casper Mountain where up to 18 inches of new snow fell. Many areas around Casper and Lander, Wyoming, saw up to a foot of snow. The heavy, wet snow fell on trees with full foliage and brought down branches, limbs and in some cases entire trees. The trees fell on power lines causing numerous power outages. In western and southern Wyoming, wind was the main hazard. The strongest winds occurred in Sweetwater County, with wind gusts as high as 86 mph reported at the Rock Springs airport. Numerous trees were downed in Rock Springs and Green River, leading to thousands losing power. Portions of Teton and Sublette Counties also saw widespread tree damage and loss of power.

Source: NOAA Storm Events Database, event_id 920057. Narrative written by the NWS forecast office that issued the report.