Large avalanche in the 2nd Yellow Mule that is probably 2-3 days old, and likely broke on the weak layer near the bottom of the snowpack. Photo: GNFAC
A large avalanche in the 2nd Yellow Mule that was probably 2-3 days old, and likely broke on the weak layer near the bottom of the snowpack. Photo: GNFAC
We saw two large avalanches in the 2nd Yellow Mule that were probably 2-3 days old, and likely broke on the weak layer near the bottom of the snowpack. Hard slabs on heavily wind-loaded slopes. Photo: GNFAC
We dug in the second yellow mule, NE aspect 9,300' and HS was 93 cm. Here we had ECTP26 on the layer of facets near the bottom of the snowpack.
We saw two large avalanches in the 2nd Yellow Mule that were probably 2-3 days old, and likely broke on the weak layer near the bottom of the snowpack. Hard slabs on heavily wind-loaded slopes. Photo: GNFAC
At Buck Ridge there was a stout ice crust (maybe a rain/mist crust) about 10cm down that is not a problem at the moment, but notable due to being widespread and unusual for our normally dry snowpack. Photo: GNFAC
We dug in the first yellow mule, NE aspect at 9,400'. HS was 128cm and we had two ECTX. We identified the two weak layers we have been talking about in forecasts (see video), but they were not reactive here in our tests. We dug in the second yellow mule, NE aspect 9,300' and HS was 93 cm. Here we had ECTP26 on the layer of facets near the bottom of the snowpack. In both pits and a quick pit in 3rd yellow mule there was a stout ice crust (maybe a rain/mist crust) about 10cm down that is not a problem at the moment, but notable due to being widespread and unusual for our normally dry snowpack (see picture).
We saw two large avalanches in the 2nd Yellow Mule that were probably 2-3 days old, and likely broke on the weak layer near the bottom of the snowpack. Hard slabs on heavily wind-loaded slopes.
Pit Location: E / ESE Aspect | 8900' | 150 - 160 cm snow depth | Near Treeline | 29 degree slope
Weather at 15:20: OVC | S-1 to S1 | Winds Strong out of the WSW / SW
Test Results:
14cm down from surface; CT1 (2x) at the new snow interface, fairly soft slab without a lot of cohesion in this particular spot NTL
43cm down from surface; CT11 SP and CT17 SP, broke on a layer of small facets (~0.5-1.0mm) below this week's more recent storm snow
Did not have time to do a full ECT, however the interface was very planar and yielded a sudden collapse at the layer in question
We found the recently buried weak layer of near-surface facets one foot deep. The sugary facets lower in the snowpack were also present but neither propagated in our stability tests. Thankfully, another group dug a pit nearby. They got an ECTP20 on the near-surface facet layer one foot down. This means the layer is confirmed in Hyalite, Buck Ridge, and Lionhead. A similar story is coming out of the Bridger Range. Until proven otherwise, I am operating with the assumption that it is everywhere from north of Bozeman to Island Park. I am worried about this layer when more snow starts adding up.
The wind was blowing ~ 20 mph on the ridge and depositions of wind-drifted snow near ridgelines, in cross-loaded gullies and near wind-breaks like trees, cliffs, and outcroppings were the most likely place to trigger a slide today.
Temperatures were above freezing when we got back to the car. Some small, wet-loose snow avalanches slide from road cuts and piled up a few feet deep next to the Hyalite Canyon Road.
