Pro Field Report

Basic Information

Observation Date:

January 13, 2022

Submitted:

January 13, 2022

Observer:

SAC - Bret Rasmussen

Zone or Region:

Island Park

Location:

Lion Head bench

Recent Avalanches?

None Observed

Cracking?

Isolated

Collapsing?

None Experienced

I found a weak layer near the surface and underneath a strong dense wind slab. For now I haven't identified that this is a widespread problem and I am not seeing it on slopes that haven't been wind loaded. This could be a layer of higher concern if the wind slab it is supporting is deep or if we get a new storm snow load.

Stability Rating:

Good

Confidence in Rating:

High

Stability Trend:

Improving

I feel like we are in great shape on Lion Head. The snowpack is quite solid. We saw great results from our field tests today. The trending warmer weather is a bonus to helping solidify the snowpack even more. I saw a few isolated deeper wind slabs that deserve respect. The weak layer near the surface could become a problem after the next storm cycle, but for now it is not supporting enough weight to fail in a big way. The facet layer at the bottom of the snowpack is healing nicely where the snow is deep. I warn that in shallower snowpack this might not be the case, with the recent high winds a lot of snow has been removed from certain areas and deposited in others. Be on the lookout for potential isolated hot spots!!

Advanced Information

Cloud Cover:

Overcast

Temperature:

29f

Wind:

Light , W

New/Recent Snowfall:

Trending warmer weather. Localized blowing snow. Most of the snow available for transport has already been transported!!

Results of snow pit instability tests at 8500 feet, 38 degrees NE aspect, 19 degree slope. HS 195cm. CTEQ1@185cm, CTHQ1@167cm, CTHQ1@162cm. ECTP10@180cm. DTN. The Compression test shows that we have multiple layers of snow, while the extended column test shows the layers are bonded well enough that we get only one failure with propagation. With a deep tap test the suspect PWL at the bottom of the snowpack did not fail. It sheared off at the ground. (see photo attached) The facets at the bottom of the snowpack are turning into rounds and starting to bond. Even though I saw a 4 finger density in this layer it still supported the snow above it. The weakest layer is found near the top of the snowpack about 15cm thick with about 15cm wind slab on top of it made up of fragmented precipitation particles with fist hardness. I observed some shallow cracking caused by a sled ski or track stressing the surface wind slab.