High Wind — Southern San Luis Valley, Colorado

2021-12-15 · Southern San Luis Valley, Colorado

Event narrative

Highway 142 closed near San Luis for downed power lines across road.

Wider weather episode

A potent upper level system and surface low approached the region late in the day on the 14th, and then lifted across Colorado during the day on the 15th. As the system moved overhead a strong upper level jet of 120 KT moved from southwest to northeast across the region, from the San Luis Valley eastward into the eastern Colorado plains. This setup favored heavy mountain snow across the Continental Divide, primarily the eastern San Juan mountain. Meanwhile, lighter amounts of snow were observed across the central and eastern mountains. As this system pivoted across the region, the strength of this system and some weak instability supported the development of snow squalls from the Continental Divide east into parts of the I-25 corridor. The strong jet moving across the region as well as mountain wave action produced widespread extreme winds over much of southern Colorado. The very dry/drought conditions in place and the extreme winds then produced widespread blowing dust over much of the plains.

High/Extreme fire danger was also noted given the strength of the wind field and falling RH values, falling well into the teens, when combined with gusts over 70 MPH. Numerous grass and prairie fires occurred caused by falling power lines.

Source: NOAA Storm Events Database, event_id 997847. Narrative written by the NWS forecast office that issued the report.