More shooting cracks and remote triggering in Cement Creek

CBAC CBAC Observations

Date of Observation: 02/27/2022
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Snowmobiled on various aspects up Cement Creek to Double Top to Tilton Pass at 12,000 ft.

Observed avalanche activity: Yes
Avalanches: I remotely triggered a 16″ persistent slab on a west aspect near treeline from over a hundred yards away. Also remotely triggered a handful of very small pockets by creek beds. Observed one fresh cornice fall that produced a D1.5 avalanche. A couple of small loose wet slides ran this afternoon on steep south NTL.
Documented extensive D1 to D2 avalanche activity in the Southeast Mountains from the cycle, organized into separate obs by location. The most widespread activity was below treeline on W to N to E aspects with a lot of activity NTL on the same aspects. A couple of persistent slabs might have run today. Above treeline had the fewest slides, which makes sense because the faceted snow surfaces in the alpine in this area were heavily worked by winds prior to the storm, except for Cement Mtn. Above treeline had a handful of slides that failed on SE and S aspects as well.
Weather: Clear and calm. Cold start, mild day.
Snowpack: This area got the least amount of snow from the storm and the persistent slab problem is smaller and more manageable than what I’ve found in the Northwest Mountains. Slabs average about a foot thick: less than 10″ in Lower Cement, and up to 18″ near the headwaters, generally fist hard below treeline and up to 4F or 1F in driftier areas at higher elevations. The 2022 BS sandbox layer is as weak as ever here in sheltered terrain: 2-3 mm and fist hard. However, signs of instability are waning on northerly terrain below treeline because the slab is very soft and faceting over a soft weak layer. The bullseye for widespread shooting cracks was on east and west aspects where there is a thin crust helping drive propagation. I got moderate propagating results on this structure (ECTP11). Once I climbed into the most wind-affected terrain, signs of instability went away. The slabs are bonding well to pencil and knife hard wind blasted surfaces, with no results in tests or slope cuts.