Granite Mountain - April Avalanche Time

As Mountaineers, we are committed to learning from our experiences. We examine every incident that happens on a Mountaineers trip for opportunities to improve the ways we explore and teach. Our volunteer safety committee reviews every incident report and picks a few each month to share as examples of ‘Lessons Learned’. The trip report below describes what happened on this trip, in the leader’s own words, and outlines the lessons the leader has identified. In some cases, we offer additional key learnings from the incident.

Sharing incidents creates an opportunity to analyze specific incidents and also identify larger incident trends. We appreciate every volunteer trip leader who takes the time to share their incidents and near-misses so that others can benefit. We ask that readers engage critically and respectfully in the spirit of sharing and learning.

Granite Mountain, Snoqualmie Pass - April 21

Leader Incident Report

LEADER

This scramble was planned for Denny Mt, but when we got to the Alpental parking lot we were informed by employees of the ski area that they would be grooming the slopes and doing avalanche control work and that we could not go up Denny. So we headed over to Granite Mountain as our backup plan. I had chosen Denny (and Granite as a backup) because I placed a premium on organizing an early season scramble that would include good places for students and rusty scramblers to practice their self-arrest skills. With all the warm rain we had that week in Seattle, I had not considered that there would be fresh snow on the mountain tops. The weather forecast for Friday was for a warm and sunny day.

NWAC did not publish their avalanche forecast until late Thursday evening. It indicated that the risks were "considerable" above tree line (and "moderate" below). I did not see the forecast until right before going to bed. In retrospect, I should have immediately planned a backup to the backup and headed for either Humpback or Cave Ridge, both of which are safe all-in-the-woods scrambles, but they offer no chance to practice self-arrest skills.

We climbed up Granite, sticking to ridgelines. We discovered that there was about 2 inches of new snow. We saw several day-old avalanches. We ran across a pair of skiers descending in the early morning who warned us off the mountain, saying that with all the solar heating and new snow, avalanches were all but certain in the afternoon. We discussed stopping at the first slope steep enough for self-arrest practice, practicing for an hour, and going home, but the group was unanimous about wanting to continue to the summit, as long as we could stay on ridges.

I noticed on the way up a region, around 4800 feet, where the 2 inches of new snow was poorly adhering to a crust underneath.

We reached the summit and were rewarded with outstanding views. On the way down, we took a zig-zag path: we would glissade for a bit (which tends to take you off the ridge crest), then traverse back to the ridge crest and glissade again.

At about 5,000 ft, I was glissading in front of everyone else. I kicked off a wet slough avalanche that took the top two inches of loose snow. I was able to dig my heals into firm snow and stop. The wet slough avalanche continued another 50 feet to a slight bench. The next student moved 20 feet to my right and proceeded to glissade. The same thing happened. At that point, I gathered us all together to discuss how to proceed. Looking around, I noticed that there was a fresh avalanche in the neighboring bowl that started at about our elevation and went down hundreds of feet.

We immediately formed a single line and traversed to the nearest ridge. Every few feet, our footsteps would kick off a wet snow slough. We must have set off several dozen avalanches. Some of the sloughs grew quite large and descended several hundred feet, gaining speed and flowing into the trees at the bottom of the bowl. It was quite exciting watching all these rivers of moving snow. We kept an eye above us to see if anything was coming down on us, but there was nothing above us to trigger anything. Even descending on the ridge line we kicked off avalanches, but they moved down the fall line and away from the ridge crest.

As things turned out, we were fine. But had we descended a bit farther, had we been a bit farther spread out, it might have been possible that part of the party above could have triggered an avalanche onto part of the party below.

Lessons Learned

The obvious lesson is to stay away from obvious dangerous mountains, like Granite, when the avalanche danger is considerable.

I have gone through the AIARE avalanche training. I lead a lot of winter scrambles. I have a reputation for being very cautious about avalanches. I know the pitfalls of group think and of being lulled by blue sky and everything going well. And yet despite all that, I somehow ended up where I should not have been.