Lionhead Range

We went to the Taylor Fork area and into Cub/Cabin Creek to see what snow surface was buried by recent snow (about 0.8" swe in this area).

It was easy to find small facets in every pit we dug (some had surface hoar as well). We looked at N, SW, W, and E aspects at elevations around 9000 ft. On a north aspect, they were 1mm facets chained together almost 10mm long.

Consistently these weak layer were 8-10" deep (more in areas with drifting). They produced easy ECTP's and one ECTPV.

What was remarkable is that this layer produced shooting cracks all day long. They were generally subtle but would shoot 10-50 feet.

WHAT TO DO? Now is time to shift our mindset to "stepping back". Lots of great powder is on the way. Unfortunately this snow will likely come with a lot of wind. The more snow/water and wind that come, the bigger of a step back, we'll need to take in our terrain choices. By the end of the week, we will likely be avoiding all avalanche terrain including runout zones in areas that get 3-4" of swe.

1 meter deep snowpack showing the obvious facets in the bottom third

We went to Lionhead, seeking some of the thinnest and weakest snow. We found relatively thin snow - the snowpack was mostly a 1 meter deep (3.2 ft). It was supportive for sleds and you could walk on top with about 6-8 out of every 10 steps not punching through to the ground. This is because there is a very cohesive slab on top of the early December facets.

What surprised us was how stubborn that weak layer was in our tests. We dug in 4 different places on E, E, E, and NW aspects between 8000 and 9200 feet. ECTs either wouldn't even break or would propagate on the weak layer after mid- to high 20s for taps.

We observed some new facets near the snow surface that formed last weekend during very cold weather. On Lionhead Ridge we found these facets capped by a hard but thin (~4 inch thick) wind slab. 
 

Summary

• The early December faceted layer seems mostly dormant for now.
• Wind slabs are the main problem and they will be extra sensitive as more snow comes Friday providing winds more ammo to make the wind slabs deeper. Because these wind slabs may be resting on facets, they could stay a problem for sometime.
• We did not get a chance to map how widespread or isolated this wind slab/facet combo is.

From FB message 1/19: "In between redstreak peak and white peak... The whole slope cracked...  the one I stopped on I put my leg in the crack and went to my knee inside the crack"

Screenshots from videos sent in messenger

This morning we went touring at Hebgen up to the ridgelines near the northern end of the lake. Winds were calm for the duration of our tour. Snow depths are still pretty shallow relative to much of the advisory area, around 95cm HS on the ridgelines at 9000 feet. We experienced no cracking or collapsing but kept a high degree of suspicion due to the shallow, weak snowpack and stayed off avalanche terrain. 

We encountered widespread surface hoar on east aspects above 8000 feet. There were enough intermittent clouds and lack of winds that I suspect it could be buried by the next round of snowfall. Time will tell!