The Skyline has received above average snowfall during the 2010-11 winter season. Unfortunately, a wide spread surface hoar event occurred and was buried intact in early January. An unusual rain event occurred on January 16th producing a rain crust that was quite stout in many areas. Faceting associated with the crust occurred during a period with fewer storms at the end of January and into February. The buried surface hoar and facets that formed under the crust have produced very scattered avalanches. However, these avalanches have been large and dangerous. Recent snow storms with more wind then normal has made these buried weak layers become more active.
Forecasters and backcountry observers have been noting and speculating about this weakness since it's formation. While it hasn't produced a large number of avalanches, it's scary nature has made the forecasters continue to include it in the avalanche advisories.
About 12" of new snow had accumulated over the few days prior to the avalanche. Skies were partly cloudy. Southerly winds were in the moderate speed category which is very common along the Skyline. Some drifting was occurring.
It should be noted that the forecasters that investigated this avalanche were shut down by white-out conditions just prior to doing a crown profile (looking at the weak layers). It is assumed that the avalanche broke into faceted snow due to it's depth and since it revealed rocks where faceting is likely to have occurred. The short window of clear weather did not allow the forecasters to dig and look at snowpack layering at any adjacent terrain that would be representative of the avalanche site.
The accident occurred in The Big Shoe or The Big Horseshoe. The aspect of the avalanche was northeast. The slope angle was approaching 40 degrees. A rock band runs horizontally through the upper portion of the bowl. This made the slab above the rock band basically unsupported. The rock band was just covered and a few rocks could be seen poking through the snowpack on adjacent paths. This thin rocky terrain is subject to faceting or in simple terms, the snow becoming weak. Just south of the bowl is an enormous flat fetch which is a perfect place for the southerly winds to pick up loose snow and deposit it into the bowl.
Events Leading to the Avalanche
Heading south on highway 89, just before you get to Fairview, UT, you get a glimpse of the Mountains of the Manti Skyline. One of the most striking features is the Horseshoe bowl with its steep north facing tree chutes. 7 Skiers from Utah were captivated by that bowl some time ago. After spending time planning & thinking about the captivating shot, they set out to ski it on March 26th, 2011.
These are expert skiers; most of the party has been skiing since childhood. Backcountry experience amongst the members of the group ranges from 2 – 14 years. Each member of the group was carrying beacon, shovel & probe, and they had all practiced with their gear. Most members of the group had taken a Level 1 recreation avalanche course. A few members of the group had read the current avalanche forecast in its entirety which rated the overall hazard as Moderate with pockets of Considerable with “the possibility for deep slab avalanches on steep rocky upper elevation slopes facing the north half of the compass.”
The group left the Ephraim Canyon trailhead in the morning in a modern snowcat, reaching the Horseshoe Bowls after a couple hours of travel. Visibility was good, although it was windy, and they noticed a storm brewing to the west on the Nebo side of the valley.
The group observed that the Little Shoe Bowl was actively wind loading, so they moved over to the Big Shoe Bowl. Once there, they put one person on belay. That person, now tied in, went out to the massive cornice and started cutting and kicking pieces of cornice onto the slope to test for stability. These cornice drops produced very small loose snow avalanches aka sluffs. The group thought these sluffs were a manageable avalanche hazard & decided to send a two members into the slope to conduct more snow stability testing. A & B got into the upper part of the slope and dug down 6’ or so. They then conducted a few compression tests which resulted in sudden planer shears 16” in depth. All members of the group commented how they didn’t like the results. A & B then moved a few feet to a different location to conduct a few more tests. The results were similar, and the group came to the consensus that they didn’t want to ski this slope. They began gathering their gear to leave the area.
At that point C & D were standing near the edge of the cornice which suddenly gave way. C fell with the VW Bus sized piece of cornice that broke off and triggered the large avalanche. C was carried almost all the way down the avalanche path. Viewing from above, D saw C get up and start moving around and for a moment the group thought they had dodged a bullet. They soon realized that A & B had also been caught and carried by the avalanche. D instructed E, F & G who were waiting in the snowcat to call 911 which they did as there is cell service at this location. This call was placed around 11:45am & EMS was mobilized.
D then switched his beacon to receive and went down the slope to start the rescue of A & B. As D arrived at the debris pile he found C searching, and C & D got to B who was buried, but had his head & one arm free. They cleared B’s mouth, and then E arrived on the scene and dug B the rest of the way out.
Leaving E to continue digging, C & D searched for A’s beacon signal which they quickly acquired. Using their beacons, they followed the flux lines to A’s location and found a ski boot heal on the snow surface. A was almost completely buried, and appeared to have suffered serious trauma during the avalanche. The group worked in shifts to quickly & efficiently dig A out. Once out of the snow, A had no vital signs; he was blue in the face, not breathing and had no pulse. Heroically, the group began the exhausting work of administering CPR. They did so for a full hour. Just as they contemplated stopping, A’s chest rose on its own and a pulse was detected, although he did not regain consciousness. The group administered rescue breaths for the next two hours while keeping A as warm as possible. The group was utterly exhausted at this point, now waiting for SAR teams to reach them to help get them & their critically injured friend up and out of the steep bowl.
The party estimates they got to B in 8 minutes & had A dug out 15 minutes after the avalanche was triggered which is nothing short of amazing given the circumstances & the size of the avalanche.
At this point SAR teams composed of over 75 volunteers from both Sanpete & Sevier Co. were battling absolutely epic conditions to get to the party waiting in this very remote location. A storm had rolled in and reduced the visibility to just a few feet, further complicating the situation. Eventually, SAR teams were able to deploy over 2100’ of rope to get down to the party. SAR teams brought food, water, started a fire to warm the group and began the long & arduous process of getting the skiers back to the top of the bowl, a distance of over 1000’ vertical feet.
In an amazing show of strength and determination, all rescuers and victims were back on top of the ridge near nightfall. By 9:30pm all rescuers and victims were in vehicles heading back towards the highway.
Once the avalanche occurred, the party preformed a text book rescue, and really did everything right. Amazingly, they pulled their friend out of the snowpack dead, and brought him back to life. This is an outstanding effort on their part.
This accident really comes down to being in the wrong place at the wrong time. While the party was trying to do the right thing by gathering information, they were doing so in the start zone of a major avalanche path, an incredibly hazardous area & high risk activity. Unfortunately, the backcountry snowpack can be a very harsh and unforgiving judge, and the party paid the ultimate price for this mistake in the loss of a loved one. I am deeply saddened by this accident and my thoughts & prayers are with the party this evening.
SAR teams were tasked with an incredibly difficult mission in downright nasty conditions. The volunteers who boldly went out into the storm to help the victims truly embody what it is to be a hero. Had the party been forced to endure the cold stormy night out in the elements, the outcome could have been very different. Sanpete & Sevier Co. SAR, my hat is off to you. Well done.