CAIC: Colorado Avalanche Information Center

2010/12/12 - Colorado - Near Jones Pass, Front Range

Published 2010/12/23 by Spencer Logan - Forecaster, CAIC


Avalanche Details

  • Location: Near Jones Pass, Front Range
  • State: Colorado
  • Date: 2010/12/12
  • Time: 11:45 AM
  • Summary Description: 1 snowmobiler caught, partly buried.
  • Primary Activity: Snowmobiler
  • Primary Travel Mode: Snowmobile
  • Location Setting: Backcountry

Number

  • Caught: 1
  • Partially Buried, Non-Critical: 1
  • Partially Buried, Critical: 0
  • Fully Buried: 0
  • Injured: 1
  • Killed: 0

Avalanche

  • Type: HS
  • Trigger: AM - Snowmobile
  • Trigger (subcode): u - An unintentional release
  • Size - Relative to Path: R3
  • Size - Destructive Force: D2
  • Sliding Surface: G - At Ground/Ice/Firm

Site

  • Slope Aspect: SE
  • Site Elevation: 12100 ft
  • Slope Angle: --
  • Slope Characteristic: Convex Slope

Avalanche Comments

The avalanche was triggered from the slab margin in low angle terrain, 50 to 150 vertical feet below the crown.

Weather Summary

The reporting party mentioned "10 to 100 foot visibility." Observers in nearby drainages experienced periods of similar low visibility, and strong, gusty winds from a variety of directions near treeline.

Snowpack Summary

The party was on low angle terrain and had not examined the snowpack near the trigger point. On similar aspects they found three faceted layers, including very weak facets at the ground.

Events Leading to the Avalanche

The party was conscious of the avalanche conditions and was avoiding "ANY big hills...with snow on them." They mis-navigated in the whiteout, and crested a slope above terrain they planned to avoid. The rider turned around, was feet from exposed rocks, when the snow cracked.

Accident Summary

The rider was moving very slowly on low angle terrain when he saw the cracks. He "pulled into [the] rocks, thought I was out of path and would watch it go by."

The rider was hit by a "freightliner" of snow from above. He was instantly buried. He triggered his airbag and "floated to the surface as I heard the bag inflate." He was able to swim to the edge of the avalanche, and came to a stop after about 100 feet, partly buried under 6 to 18 inches of snow. "Below me was a [rocky area] that would have destroyed me, period."

The avalanche continued over the rocks and to the valley bottom. There were "car...sized blocks" left in the starting zone, and debris piles deeper than the party's 3 m probes. The rider's sled was buried and found the following day.

Comments

The CAIC forecast a "CONSIDERABLE (Level 3) danger on north through east through south aspects near and above treeline." The rider said "you didn't have to check CAIC to see" that heavy windloading and a recent storm had created dangerous avalanche conditions. The group was deliberately choosing to ride in conservative, safe terrain. A navigation error in the whiteout put the party into avalanche terrain.

Airbag backpacks are proven technology in Europe. Their adoption in the US has been slower, but use is becoming more common. As with all avalanche safety equipment, airbags do not prevent or protect you from avalanches. What they can do is reduce the consequences of being caught by making it easier to escape and decreasing burial depth. Trauma accounts for over one quarter of avalanche fatalities in the US. Airbags do not prevent trauma--with or without an airbag, the potential for fatal injury was high if the rider had gone over the cliffs. In this case the airbag allowed the rider to swim and escape in a short, scary ride instead.

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