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Weather Summary

Day started clear, with a bit of thin, high cloud cover building in the mid-late morning. This briefly limited solar input (but not much). Northerly winds blowing throughout the day with visible transport from dawn until dusk. Wind speed gradually increased around noon, beginning to dig down into middle elevation terrain and move a fair bit of snow there .

Avalanche Observations

Avalanche Observation Comments:

We observed the aftermath of dry loose slides of several vintages. Many occurred during the storm, others occurred during the several hours of clear skies the following morning, and a probably occurred today. We also saw a few small/very small slabs in steep, recently wind loaded and spin drifted terrain. These were never more than 5m wide or so.

Snowpack Observations

Rec day, my primary goal was to find some good, safe skiing (HBD Sam!)

I spent a bit of time looking at upper snowpack weak layers as well. As I reported from Banner on 3/9, the rain crust (created 3/1, buried 3/8) is pretty ugly in shaded, middle elevation terrain. I looked at it at 8,600' and 8,500' on NE, where it was buried beneath 16-18cm of recent snow. This area was not wind-loaded and the slab was F-. Despite the lack of much of a slab, I received repeated propagating ECT results (ECTP 5x2, and 6x2) with the fracture occurring below the crust. The character of this crust was very similar to what I saw at Banner: 1-2cm crust with a few small facets on top and a 1-1.5cm interval of small, very weak facets below. Distribution of this problem will be tricky (great, more complexity!). My mental model has it at its worst on the northern 1/3 to 1/2 of the compass, between about 7,800 and 9,000', but that isn't based on a ton of direct data. This will be something to watch as loading resumes.

I also looked at the character of the 1/20 interface here, but my pits weren't in a great location for this. Based on my observations of this layer while it was being created, the worst of it was scrubbed out of the central sawtooths during the multiple extended NW wind events in February that dug well down into middle elevation terrain. In addition, the terrain here is not great for this type of problem. With that said, we traveled with this problem in mind and chose to avoid the terrain where it would be at its worst (steep, middle elevation shadies). In my pits, this layer was a bit hard to pick out visually, and it presented as stiffer wind board with a broad interval of small facets on top. It produced repeated ECTNs in the upper teens to low 20s, down 45-50cm.

Wind: today's winds were moving snow at ridgetops in the morning and then began to dig down into middle and lower elevation terrain by noon. There was quite a bit of snow being transported, but it was hard to tell how much constructive slab building was going on. We did observe some big drifts and large dunes spanning entire slopes at middle elevations, and we avoided this type of snow. Glassing around, there were lots of icy sheens visible in upper elevation terrain, it seems very likely that this is the MFcr that formed during the very warm weather and rain at the beginning of March.

Surfaces: Cool temperatures and advection by the wind were preventing middle and upper elevation solars from getting wet today, but the radiation was definitely having an affect on the snow. Down lower and in more sheltered terrain a crust was forming on the surface but the snow underneath appeared to be staying dry. Warm temps and direct sun might help bake down some of this weirdness/variability before snowfall returns on Sunday.

Terrain Use

We searched out solar terrain that wasn't affected by the wind. The intention was to find high-quality skiing in areas that did not have well-developed weak layers.