Quick report
- Red Flags
- Recent Avalanches, Poor Snowpack Structure
Three different pits. The slab on top of the facets is strong, 4F to 1F, and generally a little over a meter thick. The facets underneath the slab are F to 4F hard.
Pit #1 - North aspect 9,600' HS (height of snow) 175 cms. 105 cm 4F/1F slab on top of 4F layer of facets. ECTX.
Pit #2 - SE aspect 9,900' HS 160 cms CT 22 (no ECT) down 110 cms, failing in weak, F-hard facets around a decomposing crust.
Pit #3 - E aspect 9,800' HS 170 cms ECTP28 down 105 cms, failing in 4F hard facets.
No collapsing when traveling in deeper snowpack areas, however, I got two collapses (one was very loud and booming) in thinner snowpack areas (< 1 meter).
These pits and traveling results tell me the
1. slab is quickly gaining strength and is now 1F hard in most places; and
2. the PWL is slowly gaining strength, with 4F hardness in some places.
This also tells me the strong slab on top of the PWL (which is slowly gaining strength) means avalanches are becoming less likely to trigger, but the consequences remain the same: avalanches failing 3-5' deep and possibly over 100' wide. Collapsing in thinner snowpack areas may mean avalanches failing in the PWL are more likely to be triggered from thinner snowpack areas (such as along the PC ridgeline and Millcreek) or on repeater slopes. Two examples of this are (1) the remotely-triggered slide on Saturday, 1/20 in Porter Fork in Millcreek, (2) Cardiac Ridge avalanche on Friday, 1/19.
The Porter Fork avalanche was on a likely wind-loaded slope and the PWL in this area is very weak due to a thin early-season snowpack.
The Cardiac Ridge avalanche was on a slope that had avalanched sometime over the past week, but facets remained on the bed surface and wind-loading created a new, dense slab on top of the remaining facets.
It seems we are moving in the right direction(!) with fewer collapses and a PWL that is gaining strength leading to better pit scores with ECTs, but this will take some time.
Snowpack
- Instability Comment
- <p>Above 9,000', PWL was buried 100 - 120 cms (3-4'). </p>
Dense snow with rimed crystals creating excellent travel and riding conditions. 10-15 cms new snow since Saturday. No wind-loading noted other than a couple of unreactive pockets along 10,420 ridgeline.
Rain/snow line was 6,500' - 7,000'.