CAIC: Colorado Avalanche Information Center

2019/03/07 - Colorado - Point 12118, east of Jones Pass

Published 2019/04/05 by Brian Lazar, Mike Cooperstein, Spencer Logan - Forecast staff, CAIC


Avalanche Details

  • Location: Point 12118, east of Jones Pass
  • State: Colorado
  • Date: 2019/03/07
  • Time: 1:53 PM
  • Summary Description: 1 mechanized guide caught, buried, and killed; 1 mechanized guide client caught
  • Primary Activity: Mechanised Guide
  • Primary Travel Mode: Ski
  • Location Setting: Backcountry

Number

  • Caught: 2
  • Partially Buried, Non-Critical: 0
  • Partially Buried, Critical: 0
  • Fully Buried: 1
  • Injured: 0
  • Killed: 1

Avalanche

  • Type: HS
  • Trigger: N - Natural
  • Trigger (subcode): --
  • Size - Relative to Path: R4
  • Size - Destructive Force: D3.5
  • Sliding Surface: G - At Ground/Ice/Firm

Site

  • Slope Aspect: E
  • Site Elevation: 12000 ft
  • Slope Angle: 38 °
  • Slope Characteristic: Planar Slope

Avalanche Comments

The avalanche occurred in a large, complex group of avalanche paths. Multiple starting zones likely released at the same time after a large cornice collapse near the top of the slope. The avalanche initiated on an east northeast-facing slope at around 12,000 feet, but it propagated across multiple terrain features. Starting zone aspects ranged from north-northeast to east-southeast. The wall left by the cornice collapse was over 15 feet tall. The resulting avalanche broke to the north and south of the initial collapse. There were a mix of hard and soft slabs that broke on persistent weak layers. Portions of the slide released below recent wind-drifted snow, other sections released on near-surface faceted crystals about four feet below the snow surface, and some released on depth hoar at the ground (up to 6.5 feet below the snow surface). The avalanche broke about 2,000 feet wide and ran about 1,000 vertical feet. The alpha angle was 22 degrees, which is close to the maximum distance an avalanche in this path can run. The avalanche was large relative to the path, and had a destructive force large enough to break mature trees and create a powder cloud that reached 15 to 20 feet into the air (HS-NC-R4-D3.5-G).

Backcountry Avalanche Forecast

The backcountry avalanche danger near and above treeline was CONSIDERABLE (Level 3) March 1 and 2. The CAIC issued the first in a series of Avalanche Warnings for the Front Range zone on March 3 and 4. The avalanche danger dropped to CONSIDERABLE (Level 3) near and above treeline on March 5 and March 6.

On March 7 the CAIC issued another Avalanche Warning.

”Backcountry avalanche conditions are extremely dangerous. Avoid travel in or below all avalanche terrain. Avalanches are running to valley floors and some are exceeding historic run outs. The avalanche danger is EXTREME (Level 5 of 5) for the Aspen, Gunnison, Sawatch, and Vail and Summit County zones. The avalanche danger is HIGH (Level 4 of 5) for the Steamboat and Flat Tops, Front Range, Grand Mesa, North San Juan, and South San Juan zones. These are exceptional avalanche conditions.”

The Backcountry Avalanche Forecast for the Front Range zone rated the avalanche danger as High (Level 4) near and above treeline and Considerable (Level 3) below treeline. The forecast listed Persistent Slab avalanches as the primary problem on all aspects and at all elevations, and Wind Slab avalanches as the secondary problem on northwest through east to southwest-facing slopes near and above treeline. Both avalanche problems were listed as likely. The Front Range Summary on March 7 read,

“Backcountry avalanche conditions are very dangerous. Avoid travel across or below steep slopes. Avalanches may run to the valley floors or farther than they have in years. Mitigation work triggered historic-sized avalanches along I-70, Berthoud, and Jones Pass this week. This is a sobering illustration of the potential size and consequence of avalanches today. You are unlikely to survive a brush with one of these avalanches.”

Weather Summary

The closest weather station that measures snow and snow water equivalent (SWE) is the Jones Pass SNOTEL which sits at 10,400 feet, approximately 2.5 miles to the southwest of the accident site. The closest wind site is the CAIC’s Berthoud Pass weather station which sits at 11,861 feet, approximately 4.5 miles to the northeast.

The weather was unsettled from March 1 through March 3 as a winter storm moved over Colorado. The three day storm total at the Jones Pass SNOTEL was 21 inches of snow with 1.9 inches of SWE. The snow on March 1 and 2 was accompanied by strong westerly and southwesterly winds which continued to build cornices and drift the new snow onto easterly-facing slopes. Winds turned more northeasterly on March 3 as the low-pressure system moved east of Colorado. No precipitation was measured on March 4 or 5 at Jones Pass; however, west to northwest winds blew both days loading easterly-facing slopes and increasing the size of cornices along easterly-facing ridgelines.

By the early morning hours of March 6 another powerful winter storm moved into Colorado. The Jones Pass SNOTEL measured 11 inches of snow with 0.7 inches of SWE on March 6. West to southwesterly winds were strong enough to transport snow for almost the entire 24 hour period. The snow and strong winds continued into March 7, the day of the accident, and by noon the Jones Pass SNOTEL measured an additional 2 inches of snow with 0.5 inches of SWE. The 7-day snow total was 34 inches with 3.1 inches of SWE.

Snowpack Summary

Snow that fell in late October and early November turned into weak, faceted crystals during a cold dry period in the middle of November. A stormy period at the end of November built slabs on top of the weak faceted snow, and there was widespread avalanche activity on the basal weak layers. December was characterized by small storms and strong westerly winds that drifted snow into thick, dense slabs on easterly-facing slopes and began to build cornices along easterly-facing ridgelines. Human-triggered avalanches large enough to bury or injure a person continued into late December. January was a snowy month with over 65 inches of new snow in the area around Jones Pass. Avalanche activity on the basal weak layers became more sporadic as the snowpack got deeper. February was a dry month with little snowfall. A layer of small-grained, near-surface faceted crystals formed during an extended period of clear weather at the beginning of February. This layer was subsequently buried by drifting snow and small storms later in the month. Backcountry travelers triggered avalanches on the near-surface facet layer for a few weeks after it was buried, but eventually avalanche activity on this layer tapered off. At the end of February there was a settled snow base of 54 inches at Jones Pass.

A series of warm, moist, Pacific storms impacted Colorado in early March. These storms led to an approximate 20 percent increase of the snowpack near Jones Pass in the week leading up to the accident. During the first week of March, the CAIC recorded 25 very large (D3) to historic-sized (D4) avalanches in the Northern Mountains. On March 5, The CAIC recorded two very large explosive-triggered avalanche. One in the Henderson Mine area, approximately 3 miles east of the accident site, and a historic-size explosive-triggered avalanche in the Disney Chute, approximately 7 miles east of the accident site. The CAIC also recorded a very large (D3) explosive-triggered avalanche on the morning of the accident in the Stanley slide path (3.5 miles to the east of the accident site) which closed U.S. Highway 40 over Berthoud Pass for almost 3 hours.

Events Leading to the Avalanche

A group of clients and guides met in the town of Empire, Colorado on the morning of March 7. They discussed their plan for a day of snowcat riding, and conducted the morning trip briefing. The staff included a lead guide (Guide 1), a tail guide (Guide 2), a third guide serving as the group photographer (Guide 3), and the snowcat driver. The 12 clients were a mix of skiers and snowboarders. The guides discussed the Avalanche Warning, HIGH danger rating, and current conditions with the clients. They informed the clients that they planned to stick to lower-angle terrain and to stay out of avalanche terrain. The group then drove from Empire to the Jones Pass trailhead where they boarded the snowcat. The guides went through a safety briefing in the back of the snowcat during the first ride up.

The group started the day skiing below Jones Pass. The group stuck mostly to lower angle terrain during their first five runs. For the sixth run, the guides planned to take the snowcat as high as possible and descend over the other side of the ridge into the West Fork of Clear Creek. On the ride up to the drop off point they encountered about eight feet of avalanche debris across the cat road. The avalanche released sometime that morning. The debris pile stopped their progress, so the guides decided to turn around and make a run in the east-facing terrain below point 12118.

Access to the sixth run, locally referred to as "Bootpack", requires a short hike and traverse to get from the drop off point to the entrance of the run. Bootpack has a slope angle in the mid 20s to low 30 degree range, but does cut across an avalanche path, and is threatened by steeper avalanche terrain above. The first run went as planned, and they regrouped in the meadow near the creek on the Jones Pass Road. The guides decided to make another run in the same area and they loaded the snowcat for the short trip up to the drop off point.

The group did the short hike and traverse and regrouped at the top for the seventh run. Guide 1 skied first and set the boundary on the skier’s left side of the run. Guide 3 skied part way down and positioned himself on the skier’s right side of the run to take pictures of the clients. Eleven clients skied the run one at a time and regrouped with Guide 1 on the far side of the avalanche path. The last client to descend (Client 12) was a snowboarder. He rode the steeper part of the run, but got bogged down on a low-angle bench and was about 50 feet from the rest of the group. Guide 2 descended and was near the regrouping point when Guide 3 began his descent across the avalanche path.

Accident Summary

The avalanche released at around 1:50 PM. Guide 1 and several clients said they saw the avalanche propagate from south to north and saw moving debris above Guide 3. Guide 1 yelled over the radio “Avalanche! Go Left...go...go...go!” The group lost sight of Guide 3 in the debris and powder cloud. The clients said that the avalanche “was breaking trees like popsicle sticks”, and the group thought the avalanche was going to impact them all. The powder cloud hit the entire group with enough force to push some people around. Client 12, who was moving slowly across the bench, was hit by the first wave of avalanche debris. He said he was carried in the flow and came to rest fully buried. A few seconds later a second wave of debris hit the pile he was buried in, and carried him further downhill. He could hear trees breaking as he tumbled in the debris. He finally came to rest below the regroup point on the snow surface. He was uninjured. Guide 3 was fully buried near the bench in the terrain.

Rescue Summary

Guide 1 tried to contact Guide 3 on the radio without success. Guide 1 immediately called the snowcat driver to inform him that there had been an accident. Guide 1 did a head count, and then instructed the clients to turn their transceivers off or to search. Guide 1 began a transceiver search and quickly acquired a strong signal. Guide 2 assembled his probe, and before Guide 1 could finish his fine search, Guide 2 got a probe strike. They found Guide 3 fully buried around 2.5 feet (80cm) deep. The group worked quickly to extricate him from the debris and uncovered his head within 2 to 3 minutes. Guide 3 was conscious, but it was obvious that he had sustained trauma in the avalanche.

The cat driver notified emergency medical services via radio of the accident location and asked for help. He left the cat and began heading uphill with medical supplies and a portable rescue sled. Another off-duty guide (Observer 1) from the same operation was ski touring in the area at the time of the avalanche. He and his partners were in the valley floor evaluating conditions along the northern edge of the slide path. They saw the avalanche above them, and ducked into the heavy timber. They noticed the cat on the road, and the cat driver heading uphill toward the accident site and headed toward the parked snowcat. The cat driver briefed Observer 1 about the situation, and Observer 1 took over radio communications.

Guides 1 and 2, and a few of the clients, loaded Guide 3 on the rescue sled and transported him to the cat. Guide 3 was loaded onto the cat within 25 minutes of the accident, but by that time he was showing signs of severe hypovolemic shock including a decreasing mental state.

The snowcat drove to the trailhead and met an ambulance approximately 40 minutes after the avalanche. Guide 3 was transported to the hospital. Despite the best efforts by the rescuers and medical personnel, Guide 3 later succumbed to his injuries.

Comments

All of the fatal avalanche accidents we investigate are tragic events. We do our best to describe each one to help the people involved and the community as a whole better understand them. We offer these comments in the hope that it will help people avoid future avalanche accidents.

This was a commercial guiding operation that involved guides intimately familiar with the terrain. They decided that they could manage the very dangerous conditions by sticking to low-angled terrain. The natural avalanche that covered the road forced them to change runs, but did not cause them to reevaluate their avalanche hazard assessment. The guides determined that the natural avalanche released in terrain steeper than what they intended to travel through. They therefore did not consider this a sufficient indication that their intended descent routes might be exposed to similar, but larger avalanches.

Past experience may have made them overly comfortable with the potential avalanche hazards. Their plans underestimated the threat from overhead hazard, and the potential historic size of avalanches. This was the largest avalanche to run in this particular slide path in at least 20 years. It can be easy for us to feel comfortable in terrain that we travel in often, but we need to recognize when conditions are outside of those we have experienced in the past and make more conservative decisions.

The avalanche occurred when Guide 3 and Client 12 were in lower-angled terrain at the bottom of a large avalanche path. The group avoided traveling across steep terrain, but they were traveling below avalanche terrain. Their plan notably underestimated both the threat from overhead hazard and the potentially historic size of avalanches. When avalanche conditions are very dangerous, it is important to consider overhead hazards. “Avalanche terrain” is not just a factor of the immediate slope angles, but terrain above. In dangerous conditions you should consider that the entire avalanche path is threatened by avalanches.

Similarly, the regrouping point for the clients and guides was just outside of the boundary of the solid avalanche debris. The group was close enough to the avalanche that clients scrambled to get out of the way. They were struck by the powder cloud with enough force to shove some of the clients around. Although Guide 3 was tragically killed in the avalanche, it is fortunate the avalanche didn’t break any bigger. It is possible that a larger avalanche could have put solid debris into the regroup area. 

Investigators believe that the avalanche was triggered by a large cornice fall. A third party ( two snowboarders) was in the area at the time of avalanche. It is possible that this group triggered the avalanche, but the avalanche broke several hundred feet above their last-seen location. Given the massive cornice fall along the crown line and the location of the groups when the avalanche released, we believe that the avalanche releasing after a large cornice fall is the more likely of the two scenarios. 

The guides did a remarkable job implementing the emergency response plan under very stressful conditions. Guide 3 was extricated and had a clear airway in under 3 minutes. He was in the ambulance and in the care of medical professionals within 40 minutes of the accident. Unfortunately, the rapid response did not save his life.

Our investigation included a site visit the day after the accident occurred, and interviews with the guides and surviving witnesses. We greatly appreciate their contributions, and willingness to discuss a very tragic and painful event. We would also like to thank Dale Atkins from Alpine Rescue Team who visited the site with CAIC forecasters and contributed images and expertise to this investigation.

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