CAIC: Colorado Avalanche Information Center

2021/02/16 - Colorado - West of Ruby Mountain, southeast of Rand

Published 2021/02/22 by Brian Lazar and Jason Konigsberg - Colorado Avalanche Information Center


Avalanche Details

  • Location: West of Ruby Mountain, southeast of Rand
  • State: Colorado
  • Date: 2021/02/16
  • Time: 3:00 PM (Estimated)
  • Summary Description: 2 snowmobilers caught, 1 partially buried, 1 buried and killed
  • Primary Activity: Snowmobiler
  • Primary Travel Mode: Snowmobile
  • Location Setting: Backcountry

Number

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

Avalanche

  • Type: HS
  • Trigger: AM - Snowmobile
  • Trigger (subcode): u - An unintentional release
  • Size - Relative to Path: R4
  • Size - Destructive Force: D3
  • Sliding Surface: O - Within Old Snow

Site

  • Slope Aspect: NE
  • Site Elevation: 11400 ft
  • Slope Angle: 37 °
  • Slope Characteristic: Planar Slope,Sparse Trees

Avalanche Comments

The avalanche occurred on a steep northeast-facing, near-treeline slope west of Ruby Mountain in the Never Summer Range. The avalanche was approximately 3500 feet wide and spanned several aspects from northwest through northeast to east. The avalanche broke 3 to 4 feet deep in a layer of faceted snow. It ran approximately 350 vertical feet and gouged deeper into depth hoar near the ground as it ran. The force of the avalanche snapped a few small trees and piled debris around 6 feet deep, with a couple areas up to 10 feet deep in the runout (HS-AMu-R4-D3-O). The alpha angle of the avalanche was 25 degrees. The portion of the slope where the accident occurred averaged 37 degrees in steepness near the crown. 

Backcountry Avalanche Forecast

The Colorado Avalanche Information Center (CAIC) rated the backcountry avalanche danger in the Front Range zone at Considerable (Level 3) at all elevations on the day of the accident. The forecast listed Persistent Slab avalanches as the primary problem at all elevations on north through east to southeast-facing slopes. The likelihood of triggering was rated Likely and the potential size was Large to Very Large. The summary statement read:

 

Light snowfall on a snowpack near its tipping point means that avalanche conditions are dangerous. Very large avalanches could run naturally. If you travel in avalanche terrain, you can easily trigger deep avalanches that break near the ground and run far. You can even trigger them from the lower-angled slopes below, so pay close attention to any exposure to big terrain overhead. Steep wind-loaded slopes can produce the largest avalanches, but even in wind-sheltered terrain you can easily trigger an avalanche big enough to bury you. Avoid travel on or below slopes steeper than about 30 degrees.

Sadly there were two avalanche fatalities this weekend, in two avalanche accidents. Both accidents shared common characteristics. A large and deep avalanche broke near the ground, entraining the entire season's snowpack. Our deepest condolences go out to the friends and families of both victims.

Weather Summary

The Never Summer Range saw several early-season storms in October and November. On November 16 the Never Summer SNOTEL site (located 3.5 miles north of the accident at an elevation of 10,282 feet) measured 4.6 inches of snow water equivalent (SWE), 115% of the 30-year median (1981-2010). A prolonged dry period began on November 17 with only small infrequent storms breaking the predominantly dry weather that lasted through the end of January.

The weather pattern changed near the end of January with significant storms impacting the area every few days. From February 3 to February 16 the Never Summer SNOTEL site measured an increase of 2.8 inches of SWE, a nearly 22% increase. The closest wind data comes from the CAIC’s Cameron Pass weather station (located about 12 miles north of the accident site at an elevation of 10,574 ft). This station showed moderate southwest winds through the February 3 to 16 time period. Winds speeds were generally in the 10 to 20 mph range with gusts into the 20s and 30s.

Approximately 6 inches of snow fell with moderate southwest winds in the 48 hours preceding the accident. The temperature at the Never Summer Snotel site at the time of the accident was 15 degrees Fahrenheit.

Snowpack Summary

Early season snowfall followed by dry weather produced a layer of faceted grains and depth hoar at the bottom of the snowpack. Subsequent snowfall followed by dry periods formed several layers of faceted snow on top of the depth hoar layer. The layer that this avalanche broke on (0.5 to 1 mm faceted crystals) formed in an early January dry period. This weak faceted layer was widespread throughout the mountains of Colorado. 

Storms at the end of January, and up until the time of the accident, buried these weak layers. The storm snow settled and drifted into a two to three foot thick, cohesive slab (Pencil to 1-Finger hardness on the Hand Hardness Index). The slab was very well connected across terrain features as the width of the avalanche demonstrated. These conditions were common across the region, and similar large and wide avalanches claimed the lives of two other people in two separate accidents in the Front Range, just two days prior to this accident.

Events Leading to the Avalanche

A group of 6 snowmobilers (Riders 1 through 6) departed from near the town of Gould on the morning of February 16 for a day of riding. They were aware of dangerous avalanche conditions from media reports, and their intent was to ride in low-angle slopes and meadows. They discussed avoiding steep terrain and not high-marking any steep slopes. Three riders (Rider 2, 5, and 6) were wearing avalanche transceivers, and the group collectively was carrying a few shovels and one avalanche probe. 

The group traveled south along County Rd 21. They had ridden in the area many times over the years and initially were riding in familiar areas. After about 15 miles of riding, they intersected County Rd 21A, and headed southeast along the Illinois River. They had not ridden in this drainage before. After another 6.5 miles of riding they entered a broad flat basin just west of Ruby Mountain. There were short, steep slopes above the flat terrain. They noticed a couple natural avalanches on steep northwest-facing terrain on Ruby Mountain, but they did not think this impacted their travel plans since they intended to avoid avalanche terrain.

The group spent some time riding in the low-angled terrain, and discussed avoiding high-marking or climbing on the steep overhead slopes. They were riding on the lower portions of the slopes where the terrain was more gentle than higher up. Rider 1 got his snowmobile stuck approximately 200 vertical feet above the flatter meadow where the slope angle increased to around 30 degrees. Other members of the group made a few passes by Rider 1’s location to help. They were able to free Rider 1’s snowmobile, but Rider 1 stayed in this location, off his machine, to take in the views and take some photos. Rider 5 made a fourth pass through this area when the avalanche released at approximately 3:00 PM.

Accident Summary

Riders 2 through 5 heard Rider 1 yell a warning to the group. They initially saw Rider 1 running northwest towards some trees before he turned around and ran back toward his snowmobile. At that point things quickly “got dark” as a powder cloud from the avalanche blocked out the daylight, and the group lost sight of Rider 1.

Rider 2 was slowly moving through some thicker trees to the east of Rider 1. He was making his way back towards Riders 3 through 6, and facing slightly uphill, when he was struck by the avalanche. He was partially buried up to his waist while still sitting on his snowmobile.

Rescue Summary

Rider 2 was able to quickly extricate himself from the avalanche debris packed around his legs. The rest of the group checked to make sure they could account for all members. They realized Rider 1 was missing, and began a visual search of the debris field. They could see the tip of one ski from Rider 1’s snowmobile, but no other clues. Rider 2 attempted to call 911 but was unable to get reception.

Rider 3 and 5 left the scene to ride back to their cabin in Gould so they could notify emergency response personnel.  Riders 2, 4, and 6 stayed on scene and began to spot probe for Rider 1. They only had one avalanche probe between the three of them. They also used a trail marker pole in the area as a probe. The three riders probed in the direction of Rider 1’s last seen point, and around potential burial locations near the snowmobile and in the trees in the avalanche path. They did not find Rider 1.  

Approximately half an hour after the avalanche, Rider 2 was able to get a text out to 911 at roughly the same time that Rider 3 reached 911 via phone from the cabin Gould. Search and Rescue (SAR) personnel began mobilizing around 3:30 PM.

Riders 2, 4, and 6 continued probing until three members of Jackson County Search and Rescue arrived on scene around 6:00 PM. The three SAR members and Riders 2, 4, and 6 continued spot probing until about 8:00 PM when the search was halted for the night.

The search resumed the morning of Wednesday, February 17, with members from the U.S. Forest Service, Colorado Parks and Wildlife, Jackson and Grand Counties SAR, Jackson County Sheriff’s office, two Colorado Rapid Avalanche Deployment (CRAD) dog teams from Winter Park Ski Patrol, and forecasters from the Colorado Avalanche Information Center (CAIC).  At 11:19 AM, the two dog teams began a search of the debris field. Three minutes later, a dog alerted on Rider 1’s location and the dog handlers got a positive probe strike. Rescuers dug out Rider 1 out of the snow. He was buried about 2 feet deep and had no signs of life.

Rider 1 was removed from the burial location and transported back to the trailhead with snowmobiles and rescue toboggans. Rescuers arrived back at the trailhead with Rider 1 at approximately 2:00 PM.

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 accident involved a group of experienced riders with many years of experience in this general area. Although they did not read the avalanche forecast, they were aware of the dangerous avalanche conditions in the area from media reports. They planned on a safe day of riding in low-angle terrain, and ruled out high-marking and riding on steep slopes.

Upon entering the basin below and west of Ruby Peak, they identified the steep slopes overhead as terrain to avoid. Unfortunately, they did not recognize the potential of triggering an avalanche from a low-angle slope below steeper terrain. They did not anticipate that an avalanche could break across multiple terrain features and run into an area they thought was safe. The CAIC reported numerous instances of remotely triggered and wide-breaking avalanches over the two months prior to the accident, including two fatal accidents in the same forecast zone two days earlier.

Rider 1 was not wearing an avalanche rescue transceiver. He was buried about 2 feet (70cm) deep. According to the coroner, he did not sustain traumatic injuries and the cause of death was asphyxiation. Although we will never know if the outcome would have been different if everyone in the group was carrying a transceiver, probe, and shovel; we do know that carrying and knowing how to use this equipment improves the chances of being found quickly if you are buried. Partner rescue is your best chance of survival if you are buried in an avalanche. Everyone in the group needs to carry all of the proper avalanche rescue equipment to increase you and your partner’s chance of survival if someone is buried. 

It is fortunate more members of the group were not caught and buried in this avalanche. The riders were cycling through the bottom of the slope near where Rider 1 was initially stuck, exposing multiple people to dangerous avalanche terrain at the same time. The group did not recognize that they were riding in the runout area of any large avalanche that would release. Had the avalanche released at a slightly different time, it could have caught multiple riders. It is always best practice to only expose one person at a time to avalanche terrain. This means don’t wait or regroup in avalanche runouts, don’t ride on a slope when there are other riders on the slope, and make a careful plan before you go into avalanche terrain to help your partner get their snowmobile unstuck.

Media

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Images

Snowpits

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Figure 18: Snow Pilot image of the crown profile conducted February 17, 2021