- Location: Second Creek headwall near Berthoud Pass
- State: Colorado
- Date: 2012/01/01
- Summary Description: 1 skier caught, partially buried not critical, injured
- Primary Activity: Backcountry Tourer
- Primary Travel Mode: Ski
- Location Setting: --
- Caught: 1
- Partially Buried, Non-Critical: 1
- Partially Buried, Critical: 0
- Fully Buried: 0
- Injured: 1
- Killed: 0
- Type: HS
- Trigger: AS - Skier
- Trigger (subcode): u - An unintentional release
- Size - Relative to Path: R3
- Size - Destructive Force: D2.5
- Sliding Surface: O - Within Old Snow
- Slope Aspect: E
- Site Elevation: 11900 ft
- Slope Angle: 32 °
- Slope Characteristic: --
In 2011, a very dry December followed fairly normal early season snowfall. There were five small storms with snow accumulation on Berthoud Pass in December. The last was on December 31, with about 4 inches of snow accumulating at the Berthoud Summit SNOTEL. Total snow depth at the end of December was 20 inches.
Winds were strong though the early season. The December 30-31 storm was particularly windy. The Berthoud Pass weather station recorded west and northwest winds with hourly averages between 20 and 40 mph and a peak gust of 92 mph. Winds were moderate from the northwest on January 1.
The dry and windy December left a shallow and variable snowpack in the Front Range zone. CAIC forecasters used "complicated," "variable," and "patchwork" to describe the distribution of snow and persistent slabs near and above treeline. Under the slabs, the snowpack was completely faceted.
On January 2, investigators visited the avalanche. They did a quick profile and tests near the entry tracks. There were no results with extended column tests (ECTN). Shovel and hand shears were hard but clean and fast, failing in the facets just below the thin, hard slab. Investigators caused numerous, extensive collapses near treeline and along the margins of the debris.
Events Leading to the Avalanche
Two backcountry skiers left the Current Creek trailhead, north of Berthoud Pass, on the morning of January 1, 2012. They intended to climb the ridge between drainages and ski the Second Creek headwall. They ascended south and southeast aspects near and above tree line. They did encounter some collapsing near tree line. The new wind slabs "felt good," well bonded to the old snow, and were not reactive. They reached the ridge, traveled north, and began the descent of their intended line.
The two are frequent backcountry partners. They are "good partners, who discuss lots and make conservative decisions." Both are males in their mid to late 30s and carried avalanche safety equipment. Skier 1 did not have formal avalanche training, but had read "a lot" and learned from mentors and more experienced partners. Skier 2 had more backcountry experience, and more formal avalanche training (Level 2 in the winter of 2008-09). Both had skied the Second Creek headwall in past seasons, but neither had skied the headwall this season.
Skier 2 descended from the ridge. He skied a short way down on low angled terrain to a small grassy knob on the skier's left of the face. From there, Skier 2 could see the entire run. Skier 1 then traversed south towards the skier's right side of the face. The plan was for him to ski to the right of the rock knob, about two thirds of the run, then tuck into a safe spot below the knob and spot Skier 2.
Skier 1 made several turns before the avalanche broke. He was about 150 to 175 feet below the crown face. He heard Skier 2 shout and tried to move left, off the slab. He "made little progress" and the avalanche quickly engulfed him. He was "definitely airborne" during the avalanche. The avalanche covered his face, but he could see light and was able to push up and get his face above the debris as the avalanche stopped. He was looking uphill and could see Skier 2 descending.
Skier 2 watched Skier 1 "totally disappear" in the avalanche. Once he lost visual contact with his partner, Skier 2 turned his avalanche beacon to receive and began descending the bed surface. He traversed towards the skier's right of the face and worked down. He heard a shout, but could not see anything and continued his search. He was above or adjacent to the rock knob when he heard another shout, and could see Skier 1's head. Skier 2 was not certain, but his beacon may have just acquired a signal when he made voice contact with Skier 1.
Skier 1 was buried on his side, able to face uphill. He knew his arm was broken, but was "calm and coherent for the situation." Skier 2 dug from behind, and took about 8 minutes to excavate Skier 1 carefully. Skier 1 had lost both ski poles and one non-releasable telemark ski. His legs were "pretzeled" in the snow but not seriously injured. Skier 1 did have a compound fracture in his arm. Skier 2 stopped the bleeding, splinted the arm, and they began the walk out.
The pair post-holed north towards the main trail. At times Skier 2 went "up to his armpits" in the snow while breaking trail. Witnesses in the area had called 911 immediately. The Flight for Life avalanche deployment response began, but was stopped when witnesses reported Skier 1 had been found. The pair had post-holed about a quarter mile when Flight for Life arrived for the medical evacuation. Grand County Search and Rescue had 15 rescuers in the field, and stood down once the helicopter evacuation was complete.
Skier 1 "did not fight much" once it was clear that he could not escape the avalanche. He did not know if that helped but it "did not make the situation worse." He said the pair ski terrain that is similar in steepness to the headwall, but that terrain offers more potential escape routes. They "did not leave enough room for error" on January 1.
Both skiers felt they may have become "too caught up in the goal" of skiing the headwall. They did not encounter signs of instability that made them re-evaluate their plan, and "may not have weighed the wind event" sufficiently.
Both skiers were primarily concerned with wind slabs. They chose the Second Creek headwall after reading the current CAIC bulletin. They hoped the headwall would offer a balance of wind loading, making better skiing, without too much to be unsafe. On their approach, they observed "pockets" of wind loaded snow but not any "big indications" of instability. Their intended descent route avoided the obvious wind loaded areas below the main ridge.
The CAIC forecast for January 1 mentioned that there were "also old, hard, persistent slabs above treeline whose thickness varies significantly over short distances. These persistent slabs are difficult to trigger, but the possibility remains if you find the weak spot near the thinner slab margins." Skier 1 probably triggered a persistent slab from the lower slab margin. On January 2, investigators dug a hasty pit near Skier 1's entry point. The snowpack structure and test results are consistent with a persistent slab triggered from below. Investigators found almost a foot of wind drifted snow sitting on top of a very hard (P), four inch thick persistent slab. The persistent slab was sitting on almost two feet of weak, faceted snow. The persistent slab did not break in extended column tests. It did break under hard pulls in shovel and hand shear tests, with a clean and fast fracture.
Figure 11: Hasty pit near the crown, 1-2-2012.