20-21

Natural avalanche in Yellowstone, Barronette Peak. Easterly aspects. Photo: B. Fredlund

Natural avalanche in Yellowstone on 12/24/20. Easterly aspect, and mid elevations. Photo: B. Fredlund

Fool-heartedly, I decided to attempt to ski Maid of the Mist today after experiencing false hope about the snow depth from my meander up Flander Basin yesterday. Unsurprisingly, the snowpack was horrible, very variable and faceted, and some of the worst skinning I've done in a long time. However, the snow stability was even worse than the skinning. At approximately 8600", east of Maid of the Mist Creek, I started skinning from the tree edge slightly into the north-east facing meadow. Immediately after leaving tree-line, I heard a large "whump" and noticed a faint crack that shot far into the meadow (I could only see it for 20-30 feet it was so faint, and did not show up in my photo, but it is likely it went farther from how loud the collapse was). We decided to turn around there and carefully re-traced our tracks back into the safety of the dense forest and descend back to our cars that route. As an additional note about the snow, anything solar was unseasonably hot and sticky. It appeared that a notable thermal crust could develop after today's warm temperatures.

Yesterday I toured up Flanders Peak via Flanders Creek Basin. In an exploratory gesture, I ascended via the East ridge. At approximately 9300" we dug a pit since we were setting through very variable conditions. Much of the snow was unconsolidated sugary facets all the way to the ground (approximately 95cm) underneath the new snow and we were sinking straight through to the ground as we set. However, anything slightly east south-east facing developed a nasty sun crust that was strong enough to support our weight. This was the layer we were concerned about, and while we could not get it to propagate (ETCN) in our tests, it's location (sandwiched between the new snow and the deep sugary facet base) raised some red flags for us in the future about how it would react to a heavier load piles on top of that crust. We did not ski that aspect. Instead, we skied the south-east bowl but stuck to the east aspect of the bowl. The aspect we skied in the bowl did not have that same sun crust. However, we noticed significant wind-loading the top 20 feet of the entire ridge-line and several small cornice collapses off the eastern side of the ridge. There was a significant wind crust as well (approximately 10cm), which makes sense with how windy it has been this past week. Once again, I'm sorry I have no photos to include. My phone dies in the wind.

Crown of a skier triggered avalanche on the Football Field, out of bounds south of Bridger Bowl, on 12/25/2020.

A skier triggered avalanche on the Football Field, out of bounds south of Bridger Bowl, on 12/25/2020.