15,000 trees toppled in Colorado ‘blowdown’ during 190-mph jet stream

Weather Headlines

DENVER (KDVR) — Powerful winds that ripped across parts of Colorado last September are now thought to have toppled thousands of trees in a “blowdown” event that also sent temperatures plummeting.

An estimated 15,000 trees were blown down last year during the strong cold front that left broad swathes of the woods nearly flattened, trees stacked haphazardly like matchsticks.

Behind the destructive phenomenon was a strong area of low pressure from the southwest that met a cold front racing into the northeast on Sept. 8, 2020, creating a strong cross-mountain pressure gradient.

The cold front delivered a 50-degree temperature drop and snow to the Central and Northern Mountains.  This storm system was supported by a 190-mph jet stream blowing from the southwest to northeast. 

Meteorologist Chris Tomer

At 10,000 feet, a strong northeast wind developed and ranged from 75-mph to 100-mph. The bullseye stretched from Steamboat Springs to the Devils Thumb Trail, Devils Thumb Pass, Jasper Peak, and western High Lonesome Trail.  

Nonprofit Headwaters Trail Alliance is now helping with cleanup from the devastating gusts.

The storm broke two records in Denver: It tied the 1962 record for the earliest first freeze on record. The other record it broke was a record low of 31 degrees on Sept. 9.

These were some of the biggest snow totals from that storm:

  • Alamosa: 14 inches
  • Crested Butte: 10 inches
  • Monte Vista: 12 inches
  • Westcliffe: 14 inches
  • Wet Mountains: 12 inches


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