CAIC: Colorado Avalanche Information Center

2019/11/28 - Colorado - Northwest of Searle Pass

Published 2019/12/04 by Jason Konigsberg, Kreston Rohrig - Forecasters, CAIC


Avalanche Details

  • Location: Northwest of Searle Pass
  • State: Colorado
  • Date: 2019/11/28
  • Time: 12:00 AM (Estimated)
  • Summary Description: 1 backcountry tourer partially buried
  • Primary Activity: Backcountry Tourer
  • Primary Travel Mode: Ski
  • Location Setting: Backcountry

Number

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

Avalanche

  • Type: HS
  • Trigger: AS - Skier
  • Trigger (subcode): u - An unintentional release
  • Size - Relative to Path: R2
  • Size - Destructive Force: D2
  • Sliding Surface: O - Within Old Snow

Site

  • Slope Aspect: NE
  • Site Elevation: 12000 ft
  • Slope Angle: 36 °
  • Slope Characteristic: Planar Slope

Avalanche Comments

The avalanche was a hard slab avalanche unintentionally triggered by a skier. It was small relative to the path and large enough to bury, injure, or kill a person. It broke on old snow near the ground (HS-ASu-R2-D2-O). The avalanche broke about 2 feet deep, about 100 feet wide and ran about 150 vertical feet.

Backcountry Avalanche Forecast

The Colorado Avalanche Information Center’s (CAIC) backcountry avalanche forecast for the Vail and Summit County zone on November 28, 2019 rated the avalanche danger at Moderate (Level 2) at above treeline and near treeline elevations and a Low (Level 1) danger below treeline. Persistent Slab avalanches were listed as the first problem. It was highlighted on north through east aspects near and above treeline. The likelihood of triggering was Possible and the potential size was small. 

 

Summary from the backcountry avalanche forecast on November 28 for the Vail and Summit County zone:

The avalanche danger remains elevated today ahead of another round of snow arriving tomorrow. Most lower elevation slopes where softer new snow overrides weaker snow from October are generally safe. The missing ingredient on these slopes is a stiffer slab of snow needed to produce an avalanche. On higher elevation slopes where the winds have drifted recent new snow into thicker slabs, your chances of triggering an avalanche are higher. The most dangerous slopes are near and above treeline and face north and easterly. Use caution in steep areas below ridgelines and in steep gullies where recent winds may have built slabs over weak granular snow near the ground. If you trigger an avalanche in one of these areas it will most likely be small but could take you for a rough dangerous ride.

Weather Summary

In the week before the avalanche,there were two distinct storms that impacted the region. From November 21 to 23 Vail Ski Resort (11.5 miles to the northwest) received 13 inches of new snow, while Copper Mountain ski area (3.5 miles east-northeast) received 8 inches. Westerly winds were moderate through this first storm cycle, averaging 12 to 17 mph at the nearest weather station on Copper Mountain.

The second round of snowfall started 3 days later from November 26 to 27. Less snow fell during this period with Vail Ski Resort picking up 8 inches and Copper Mountain ski area an additional 4 inches. A notable factor of the second storm was a shift in wind direction from southwest to south and an increase in average speed. Winds from November 27 to 28 ranged between 21 and 23 mph with gusts up to 47 mph. 

On the day of the incident, the winds started to ease but still blew from the south. Temperatures warmed from 28 F in the morning to 34 F by early afternoon. No new snow was recorded on the morning of November 28.

Snowpack Summary

Storms towards the end of October covered many near and above-treeline slopes in about one foot of snow. During a three-week period of high pressure in early November, this layer of snow metamorphosed into weak, faceted snow. The week before this avalanche, snow returned to the region. Coupled with ideal winds for drifting snow onto north to east facing slopes, thick slabs of snow formed two to three feet thick. The combination of a dense slab of snow resting above weaker snow near the ground created the basic structure for an avalanche. With a relatively shallow snowpack, it was easy for a person to affect the weak basal layers and trigger an avalanche.

Events Leading to the Avalanche

A family of three, two parents in their late 40s and a teenager, skied into Janet’s Cabin on Wednesday, November 28. They did not ski tour above the hut on the day they arrived. On Thursday they went out above the hut to try to find some skiing. They described the conditions around the hut as thin and rocky.

They headed southwest in search of a consistent area of snow coverage. Some of the party had been to Janet’s Cabin six times before this trip, and were familiar with the terrain around the hut.

When arriving near the slope that they intended to ski, the party made a plan on how to ascend the slope. Skier 1 would skin beneath and around the skier’s right side of the slope to check the snow conditions and confirm there weren’t too many rocks and obstacles sticking out of the snow. Skiers 2 and 3 would bootpack up a scree field, on the skier’s left, and the three would meet at the top of the slope.

Skier 1 changed his plan as he approached the slope. A cornice prevented Skier 1 from continuing on his intended route. Instead he skinned up and across the top of the slope.

Accident Summary

As Skier 1 crossed the slope and as he approached a rock band he saw the slope fracture about 30 feet above him. He yelled “Slide!” The avalanche caught him and swept him off his feet. As the debris began to  slow down, he punched his arm up into the air as high as he could. When the avalanche stopped his arm above his elbow was out of the snow but the rest of his body was buried (partially buried-critical). Snow was packed in Skier 1’s throat. He was able to use his free hand to uncover his face and move snow out of his airway. He was unable to move any other portion of his body and he said the snow felt like it set up like concrete.

Rescue Summary

Skier 2 did not see the avalanche occur. She looked back, did not see Skier 1, but  saw that an avalanche had run on the slope. Skier 2 and Skier 3 took out their avalanche transceivers and turned them to receive. Skier 3 ran towards the avalanche to begin searching while Skier 2 assembled their probe and shovel. After assembling the rescue gear, Skier 2 moved towards the avalanche. Skier 2 saw a hand sticking out of the snow and directed Skier 3 to that location. Skier 3 began to dig Skier 1 out. A short time later Skier 2 arrived to help in the excavation. Skier 2 estimated the total excavation time to be less than 2 minutes with the deepest part of Skier 1 buried 2 feet deep.

Skier 1 appeared to be uninjured. Skier 1 and Skier 3 sat and rested while Skier 2 gathered their gear together. They then returned to the hut, packed their equipment, and headed back to the trailhead. All three skiers made it back to the trailhead unassisted.

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