The ongoing storm continues to push the snowpack to its breaking point. As the slab continues to grow and settle the likelihood of impacting the weak layer as a person decreases, but that's not much to hang your hat on.
Afternoon tour. Snowing S-1 to S1 throughout tour. Light winds gusting moderate at lower and middle elevations, it sounded like it was blowing harder further up but I did not enter upper elevation terrain on this day. Difficult to tell how much it is actually snowing on each day, but based on tracks in previous skin tracks and texture/consistency of the snow, 40-50cm in the past 24 hours seems appropriate.
In this area the slab that was built over the previous 2 weeks is now 130-140cm thick, HS=175-185cm. Upper 60cm are in the F- range, then grading pretty smoothly down to P- at the base of the slab. Continuing to get propagating results in ECTs (ECTP 22 and 24) and very short cut lengths in CPSTs (CPST 28/140, and 36/140, both END). Results are from a pit at 8,200' on N facing slope. See video attached below.
I've been seeing some consistent dirty shears in the upper snowpack but nothing terribly alarming (yet). Most obvious seems to be about 50 cm down, roughly corresponding to either a change in PP or perhaps a quick hit of FCsf from the window of clearing on 12/24? Impossible to distinguish visually, mostly just apparent by how the snow behaves in shovel shears. Continuing to monitor.
|Deep Persistent Slab
Dec 11, 2021 (FC)
Comments: Rose shaded based on where problem is known to exist, based on previous observations.
I did not directly encounter either a storm slab or wind slab problem in the terrain I traveled in. But, based on remote observations I'm sure a wind slab problem exists in upper elevation terrain and likely at the upper end of middle elevations as well.
As with many places we are trending towards a deep slab instability here, but given the rate of ongoing loading and slab creation, it is a bit hard to want to describe it as that until after the dust settles a bit.
Continuing to avoid avalanche terrain where 12/11 is present as anything other than the ground.