CAIC: Colorado Avalanche Information Center

2020/12/19 - Colorado - North Face of Battleship, southeast of Ophir

Published 2020/12/24 by Spencer Logan, Jeff Davis, Chris Bilbrey, Mike Barney and Rebecca Hodgetts - Forecasters, CAIC


Avalanche Details

  • Location: North Face of Battleship, southeast of Ophir
  • State: Colorado
  • Date: 2020/12/19
  • Time: Unknown
  • Summary Description: 2 backcountry skiers caught, buried, and killed
  • Primary Activity: Backcountry Tourer
  • Primary Travel Mode: Ski
  • Location Setting: Backcountry

Number

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

Avalanche

  • Type: SS
  • Trigger: AS - Skier
  • Trigger (subcode): u - An unintentional release
  • Size - Relative to Path: R2
  • Size - Destructive Force: D2.5
  • Sliding Surface: O - Within Old Snow

Site

  • Slope Aspect: NW
  • Site Elevation: 11155 ft
  • Slope Angle: 30 °
  • Slope Characteristic: Sparse Trees

Avalanche Comments

This was a soft slab avalanche triggered by the group of skiers. The avalanche was small relative to the path and destructive enough to injure, bury, or kill a person. The avalanche failed on a 15 cm thick layer of faceted snow (SS-ASu-R2-D2.5-O). The crown face of the avalanche was 12 to 20 inches deep and about 700 feet wide. At the crown of the avalanche, the most recent snowfall sat above a firm, wind-stiffened surface that developed during a strong wind event on December 15. Several hundred vertical feet below the crown face, the snowpack was not wind affected, the weak layer was softer, and the slab was more cohesive. This was a Persistent Slab avalanche.There were two avalanches in the main bowl to the east that released sympathetically to the the fatal avalanche (SS-ASy-R2-D2-O)

The avalanche occurred on a steep, northwest through north to northeast-facing slope above treeline, locally known as the North Face of Battleship. The avalanche ran 1600 vertical feet, from the alpine into a below treeline creek bed.

Backcountry Avalanche Forecast

The Colorado Avalanche Information Center’s (CAIC) North San Juan zone rated the avalanche danger as Considerable (Level 3) near and above treeline, and Moderate (Level 2) below treeline. The forecast listed Persistent Slab avalanches as the primary problem at all elevations on west through north to southeast-facing slopes. The likelihood of triggering was Likely and the potential size was Small to Large (up to D2). The summary statement read:

Recent snowfall has thickened slabs above weaker snow inching the snowpack toward its tipping point. Slopes that have not failed naturally may be sitting there waiting for the extra push from a rider or machine. For today, the threat of triggering an avalanche remains elevated and you’re more likely to get into trouble on west through north to southeast-facing slopes. Areas harboring the thickest drifts are the most dangerous and where a small slide could trigger a larger, more deadly one. Strong northwest winds today may help thicken and expand the distribution of wind-drifted slabs below ridgeline and in cross-loaded terrain features.

Treat any steep slope where you see evidence of recent wind-loading, textured snow surfaces, or smooth rounded pillows of snow, as suspect. Although the size of avalanches that you can trigger will be smaller below treeline, these avalanches can be just as dangerous if you are pushed into trees or buried in a terrain trap. Pay attention to surface cracking, audible collapses, and stick to slopes less than 35 degrees to help reduce your avalanche risk.

Weather Summary

The CAIC measures snow and snow water equivalent (SWE) at a study plot on the top of Red Mountain Pass, five miles north and at a similar elevation to the accident site. In November, forecasters measured 42 inches of snow and 4.55 inches of SWE. There was one small storm between November 26 and December 10 with 3 inches of snow. Snowfall from December 11 through 15 added  21.5 inches of snow with 1.45 inches of SWE. Forecasters measured 7 inches of snow with 0.5 inches SWE on December 17. 

Temperatures at Red Mountain Pass remained below freezing from December 10 to 18. Temperature rose rapidly on December 19, from 5 degrees Fahrenheit at 8:00 AM to 34 degrees by 11:00 AM.

Winds at the Eagle weather station, three miles north of the accident site at an elevation of 12,852 feet, were predominantly from the east in early December. On December 16 winds were moderate to strong out of the north northwest. Winds shifted to the southwest and became light on December 17. Winds shifted back to the northwest on December 18, and increased in speed through December 19 with sustained winds above 30 mph and gusts to 46 mph.

Snowpack Summary

Two to three feet of snow fell in November. Storms arrived warm, accumulating dense snow. The snowpack faceted during a two-week period of cold, dry weather from late November to early December. On slopes with less than about four feet of snow, the entire snowpack turned into weak faceted grains. In areas with deeper snow, the faceting was most pronounced near the surface and near the ground. 

Small storms in mid-December buried the faceted snow one to two feet deep. Each storm  pushed the snowpack closer to its breaking point. The CAIC documented 142 avalanches in the North San Juan zone between December 7 and 19, with 40 occurring below treeline on northwest through northeast-facing slopes.

In the starting zone of the North Face of the Battleship, terrain characteristics result in intense drifting of snow onto the slope with southwest wind and scouring of snow from northerly winds blowing upslope. The middle and lower portions of the avalanche path are wind-sheltered and not as affected. The steepness of the terrain and north aspect mean the slope is shaded throughout the winter. On December 19, investigators noted the majority of the avalanche path was shaded before noon. The shaded slope increases faceting and allows weak snow to persist.

Accident Summary

Skiers 1 and 2 left Durango on the morning of December 19. They planned to ski in an area north of Point 12442, locally known as the Battleship. They were both very familiar with the terrain. They left the trailhead at the winter closure of CR8 (Ophir Pass Rd) around 10:00 AM. They skied up the road for about one mile before descending a south-facing slope into Mineral Creek. From the bottom of the drainage, they climbed east and into the lower portion of the North Face of Battleship.

The pair made one run on the climber’s left, or east, side of the North Face of Battleship. They ascended debris from a previous avalanche and descended adjacent to it. From the bottom of their first run, the pair ascended to the west through sparse trees towards the center of the North Face of Battleship.

There were no witnesses to the avalanche, but we suspect Skiers 1 and 2 were traveling uphill at the time of the avalanche. The burial locations and the trajectory of the avalanche debris also suggest the pair were fairly close together when enveloped in the moving debris.

Rescue Summary

Around 8:00 PM, Skier 2’s wife called authorities to report the overdue pair. She said the pair planned to ski an area known as the “Battle Scar,” east of the North Face of Battleship. A search began. 

San Juan Search and Rescue deployed and began searching. A Flight for Life helicopter flew over and reported “significant avalanche activity” on the North Face of Battleship. San Juan Search and Rescue staged three rescuers a few miles up Ophir Pass road with a megaphone calling out into the night. With no further information regarding the locations of the missing skiers, significant avalanche danger, weather, and hazards associated with traveling in the backcountry at night, the search paused at 11:00 PM. 

Three close friends of the pair decided to search independently. All three were very experienced backcountry travelers, and included an emergency room physician. The three left the Ophir Pass trailhead around 10:00 PM. They followed tracks to the base of the avalanche debris and conducted a transceiver search. They located and excavated the bodies of both skiers by 12:00 AM. The three marked the bodies’ locations and returned to the trailhead by 2:00 AM.

Skier 2 was found first, buried with just his hand above the snow (partially-buried critical). Debris covered him one to three feet deep, with his head about 1 foot below the snow. Skier 1 was completely buried four to six feet deep, about 100 feet uphill of Skier 2. Both skiers had deployed their avalanche airbags. They were buried around an elevation of 11,100 feet.

The bodies were recovered on December 20. Multiple agencies were involved in the search and recovery, including the San Juan County Sheriff's office, San Juan County Search and Rescue, San Juan/Silverton Ambulance, La Plata County Search and Rescue, Flight for Life Lifeguard 5, and the Colorado Avalanche Information Center.

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.

Skiers 1 and 2 were very experienced backcountry travelers. The three friends who found the bodies were likewise experienced. The three rescuers were willing to accept a level of risk that was not appropriate for Search and Rescue. While they found the bodies hours before Search and Rescue would have, the swifter discovery did not change the outcome of the accident.

The lower 600 vertical feet of the North Face of Battleship is generally less than 30 degrees in steepness. The slope is studded with small trees, but otherwise open. The wind-sheltered and shady location means the snow is often soft powder. These factors make the slope attractive for skiing. There were many tracks from skiers who had skied the lower slopes in the days prior to the avalanche, and other groups were touring in the general area on December 19.

The lower 600 vertical feet of the North Face of Battleship is below an avalanche starting zone almost 2000 feet wide and 800 feet tall. The low-angled slopes are exposed to a significant overhead hazard. Traveling in this terrain means all members of the party are potentially exposed to avalanches simultaneously. This exposure is critical to consider when recent avalanche activity contains wide propagation or has been remotely triggered. Both were present in avalanches observed in the preceding days. This was the second accident in the Battleship area where avalanches started above the group and caught the entire party.

Investigators classified the avalanche as skier triggered (ASu) based on data gathered on December 20. Investigators encountered localized whumpfing and crackings, indicating easily-triggered avalanches. Tests conducted during snow profiles indicated high propagation potential (ECTP12, ECTP20). Skiers 1 and 2 likely triggered the avalanche from below the starting zone. On December 19, other backcountry skiers in the area noted the crown of the avalanche by 2:30 PM. Skiers 1 and 2 were buried at least 10 hours before the three rescuers found them. 

Media

Images

Snowpits

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Figure 11: Snow profile observed in the avalanche crown.
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Figure 12: Snow profile observed in the avalanche crown.