Winter Storm — Sierra Madre Range, Wyoming

2023-12-01 to 2023-12-04 · Sierra Madre Range, Wyoming

Event narrative

Multiple SNOTEL sites suggest a total of 3 to 5 feet of snow fell in the Sierra Madre Range in the 3-day period from 12/1 to 12/4. A maximum estimated total of 54.8 inches was recorded at Little Snake River (LITW4), 12 miles SW of Encampment at an elevation of 8928 feet.

Wider weather episode

An extremely active weather pattern remained in place across the central Rockies during this time period, mainly characterized by a parade of weather disturbances embedded within an unusually strong mid and upper-level jet stream. This weather pattern resulted in persistent moist orographic ascent over the higher terrain of the Snowy and Sierra Madre mountain ranges, leading to an extended period of very heavy mountain snowfall. SNOTEL observations suggest 4 to 6 feet of snow fell in the mountains over this 72-96 hour period. In addition to the mountain snow, the elevated flow aloft combined with strong pressure gradients and strong subsidence resulted in multiple waves of strong winds with gusts 65-75 MPH, initially starting in the southeast Wyoming wind corridors before eventually spreading into the adjacent valleys and high plains.

Source: NOAA Storm Events Database, event_id 1146153. Narrative written by the NWS forecast office that issued the report.