- Location: Gibbs Creek, near Wolf Creek Pass
- State: Colorado
- Date: 2012/02/16
- Summary Description: 3 skiers caught, 1 injured, 1 partially buried, 1 buried and killed
- Primary Activity: Backcountry Tourer
- Primary Travel Mode: Ski
- Location Setting: Backcountry
- Caught: 3
- Partially Buried, Non-Critical: 1
- Partially Buried, Critical: 0
- Fully Buried: 1
- Injured: 1
- Killed: 1
- Type: SS
- Trigger: AS - Skier
- Trigger (subcode): u - An unintentional release
- Size - Relative to Path: R4
- Size - Destructive Force: D2.5
- Sliding Surface: O - Within Old Snow
- Slope Aspect: W
- Site Elevation: 11500 ft
- Slope Angle: 40 °
- Slope Characteristic: Sparse Trees
The avalanche (SS-ASu-R4-D2.5-O) was a soft slab triggered by skiers. It was large, relative to the path, and capable of burying a person. It was about 36 inches deep, and broke on a thin layer of small faceted crystals that probably formed in late January. It was 600 feet wide and ran about 500 vertical feet. It was on a west aspect below treeline, starting around 11,500 feet. The avalanche was probably triggered at roll where the slope steepened to 44 degrees near the skier's right flank of the avalanche. It propagated uphill into terrain that was about 35 degrees in steepness. Trees in the avalanche path showed evidence of flowing snow 10 to 12 feet deep.
There was a storm February 12 to 15. Storm totals on Wolf Creek Pass were 30 inches of snow and 1.93 inches of snow water equivalent, and it was the second largest storm of the season. Prior to the accident, temperatures were seasonal and winds light from the south-southwest.
Early season snowfall was abundant near Wolf Creek Pass. There was a three-week dry spell from just before Christmas until mid-January. From mid-January a there was a procession of storms with modest snowfall. Brief periods of clear weather in between created numerous layers of surface hoar and near surface facets. The February 12-15 storm topped these older layers.
Events Leading to the Avalanche
Skier 3 toured on Wolf Creek Pass the weekend prior to the accident. He found better snowpack stability and riding conditions than in other areas of the state.
The party snowmobiled up the Lobo Overlook road on 2/15, the day prior to the accident. They toured west along the main ridgeline above Gibbs Creek. They split up and dug snow pits on north, northeast, and east aspects. The party remotely triggered an avalanche (SS-ASr-R2D2-O) on an easterly aspect, but did not see it until later in the day. In all three pits, they found moderate to hard test results on buried surface hoar layers. The surface hoar was less pronounced and test results best on the easterly aspect. The party made several runs on lower angled terrain.
They moved back along the main ridgeline to westerly aspects near Lobo Overlook. They did not find surface hoar layers in snow pits, and skied several runs on treed terrain into Gibbs Creek. They had a view back and were able to see the remotely triggered avalanche.
On 2/16, the party again snowmobiled up the access road. They moved about 200 yards south of their previous tracks, into steeper west facing terrain. They dug a snow pit on a 35 degree, west aspect in the upper part of the avalanche path. Test results were moderate to hard (CT18 RP, CT23 RP) on interfaces in the upper snowpack. There were no test results on the deep weak layer that would eventually avalanche. Investigators found similar results during the crown profiles the day after the accident. Ski cuts produced nothing but small loose avalanches. They made one run, climbed back to the top, and began a second.
They began their second run around 11:45 am. Skier 1 descended a glade through the trees. He stopped at the bottom of the slope, in a pre-identified area below dense trees.
Skier 2 descended the slope. He probably triggered the avalanche at a roll-over where the slope abruptly steepened. There were rocks extending through the bed surface, though the party saw no indications of shallow snow prior to the avalanche. The crown was about 50 feet uphill of Skier 2. The avalanche propagated far to the skier's left.
The avalanche caught Skier 2. It carried him through the glade and into the timber below. He was fully buried on the uphill side of a tree, about 5 to 6 feet deep. The avalanche stripped away much of his equipment, including his helmet.
The avalanche caught Skier 3 near the crown. He was dragged downhill by the flowing snow, hit several trees, but was not buried. Skier 3 was injured and lost a ski.
Skier 1 heard the avalanche coming and saw it flow past the trees. Debris did flow through the dense trees. There was little force left by the time it reached Skier 1, and he was buried to his knees and able to sidestep up and out.
It took several seconds for Skier 1 and 3 to establish voice contact. Skier 1 began a beacon search, and got an intermittent signal "almost immediately, at maximum range of 45." Skier 1 climbed the slide path while Skier 3 slid down. They converged on Skier 2's location. They got a probe strike on the first attempt, approximately 3 minutes after the avalanche.
They began to dig. They used probes to refine Skier 2's body position. "It took a lot of effort" but they estimate they reached Skier 2's face and established an airway in 8 to 12 minutes. They called 911 and began CPR. The pair expanded the hole enough to move Skier 2 into a reclining position and continued CPR.
Wolf Creek Ski Patrol was notified shortly after 12:00 PM. They assembled a hasty team including avalanche dogs and advanced life support equipment, and took a snowcat towards the overlook. Through cell phones and whistles, the hasty team quickly found the party. They took over medical care just before 1 PM. Archuleta County Search and Rescue with the help of Wolf Creek Ski Area owner Davey Pitcher removed Skier 2's body that evening. Skiers 1 and 3 left the backcountry with minimal assistance from rescuers.
This was an experienced and well-equipped party. The companion rescue was swift. They had medical skills to assess Skier 2's most significant injuries.
Reflecting on the accident, Skier 1 felt the party did not overlook information and that nothing really would have changed their decision to ski the westerly aspects. Pondering a little further, Skier 1 said that the trees might have given them a "false sense of security." The "thickness of the trees doesn't matter" to an avalanche.
Researchers developed Obvious Clues
(ALPTRUTh) from avalanche accident investigations. The list can help identify various indicators of avalanche hazard. In the original study, almost three quarters of avalanche accidents occurred with three or more clues present. In this accident, four clues were present on the slope that avalanched, and two other clues were present on other aspects.
- Avalanches: Yes, but on other aspects. Natural and remotely triggered avalanches were on north, east, and south aspects.
- Loading: Yes. A significant storm that added a large load to the snowpack had ended less than 48 hours before.
- Path: Yes. A know avalanche path, with slope angles 35 degrees and steeper. The slope angle at the probable trigger point was 44 degrees.
- Traps: Yes. The slope was studded with trees, increasing the potential for trauma in the event of an avalanche.
- Rating: Yes. The CAIC forecast for the South San Juan zone was Considerable (Level 3) for all aspects and elevations.
- Unstable Snow: Yes, but on other aspects. The remotely triggered avalanche was a major sign of instability. The party chose the westerly aspects for their lack of apparent instability. Snowpack tests and several runs prior to the accident reinforced that sense of stability.
- Thaw: No. Temperatures near or above freezing were not a factor.
Figure 8: Crown profile from 2/17.