24-25

While looking for a recent avalanche from the flat bench above we triggered a similar sized slide directly adjacent to the previous slide. They broke on weak layers of facets and surface hoar that formed at the end of January. 2-3 feet deep and 150-200' wide. Photo: GNFAC

While looking for a recent avalanche from the flat bench above we triggered a similar sized slide directly adjacent to the previous slide. They broke on weak layers of facets and surface hoar that formed at the end of January. 2-3 feet deep and 150-200' wide. Observing the snowpack that caused the avalanche. Photo: GNFAC

While looking for a recent avalanche from the flat bench above we triggered a similar sized slide directly adjacent to the previous slide. They broke on weak layers of facets and surface hoar that formed at the end of January. 2-3 feet deep and 150-200' wide. Photo: GNFAC

While looking for a recent avalanche from the flat bench above we triggered a similar sized slide directly adjacent to the previous slide. They broke on weak layers of facets and surface hoar that formed at the end of January. 2-3 feet deep and 150-200' wide. Photo: GNFAC

While looking for a recent avalanche from the flat bench above we triggered a similar sized slide directly adjacent to the previous slide. They broke on weak layers of facets and surface hoar that formed at the end of January. 2-3 feet deep and 150-200' wide. Photo: GNFAC

An avalanche that was triggered two days ago (Feb 22), remotely from flat terrain above a steep slope, on the northeast end of Mt. Abundance. Photo: GNFAC

We went to look at an avalanche that was triggered two days ago, remotely from flat terrain above a steep slope, on the northeast end of Mt. Abundance. While looking for the avalanche from the flat bench above we triggered a similar sized slide directly adjacent to the previous slide. They broke on weak layers of facets and surface hoar that formed at the end of January. 2-3 feet deep and 150-200' wide. 1F to P- hard slab above the weak layer with 25cm of 4F to F snow at the surface. AFr-HS-R3-D2-O.

We also saw at least 3 rider triggered wind slabs, 4-5 natural wind slab avalanches, and a couple large cornice falls.

Strong wind had affected almost every piece of terrain, scouring some slopes, loading others, just stiffening the slab in many areas, and forming fresh drifts on every convex roll and along the edges of trails. Riding was still soft and fairly consistent in many areas.

I expect wind slab avalanches will be easy to trigger for a day or two more due to how reactive drifts were today... and it is still blowing and snowing a little more tonight.

The persistent slab avalanche problem is tricky because we have not seen any other avalanches of this type near Cooke City and it seems isolated, but slopes that harbor that instability might have just reached a tipping point with this round of wind-loading and dense snow, so it seems possible we could see a couple more of these avalanches over the next couple days or later this season. It will be a good idea to step back from most slopes steeper than 30 degrees during this wind-loading event, especially slopes with larger consequences like trees, cliffs and just generally large steep slopes.

From email: Came out of Hyalite around 1:30 today. There were several small slides to the road in the canyon. One slid all the way to bare ground.