Reactive wind slabs were the primary concern today, but they were generally small. Stomping, ski cutting, and a cornice drop produced a few small wind slab avalanches. The largest was around 50 feet wide and up to a foot deep. The others were smaller. Early season persistent weak layers can still be found buried 2.5-4 feet deep at upper elevations.
Wind was limited to fully exposed ridgelines, timbered ridges had light wind. Sputtering S-1 while I was out from 11am-4pm, with 2-3cm accumulation.
# | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
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2 |
Above Titus Lake NE 9800 |
D1 | SS | I-New/Old Interface | 20-30cm |
AS-Skier c-Intentional |
The larger of the two wind slabs (in the photo) was triggered intentionally by Chris Marshall by a cornice drop. It was approximately 75 feet wide. I triggered a smaller wind slab just skiers left of his slide - about 30 feet wide. |
HS ranged from 100cm at the highway to 150cm on upper elevation shaded slopes.
9560', E, 31*: HS 150cm. The usual weak layers were present near the base of the snowpack. 11/26 was down 130cm and presented as 3-4mm DH on a MFcr. It seemed to be gaining a bit of strength and was 1F-/4F+. 12/7 was 120cm down and 12/31 was 90cm down. ECTX, although removing part of the block and hitting hard produced a propagating result on 11/26.
9700, SE, 29*: HS 140cm. Primary weak layer seemed to be 12/31 which was 4F FC 80cm down, but ECTX even with very hard hits and after removing some of the block. Basal snow had gained significant strength.
In both pits and in a number of handpits, there was a thick (10-15cm) FCsf layer about 30-35cm down. The snow above it had no slab properties and it produced no results in tests. We'll see if it lasts until we get a load in this area...
Problem | Location | Distribution | Sensitivity | Size | Comments |
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Wind Slab |
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Layer Depth/Date: 15-30cm/today Comments: Would likely need to be in alpine terrain to get a size larger than D1. While there were a few intentionally triggered wind slabs, there were a number of loaded ridges I ski cut with no results. |
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Persistent Slab |
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Layer Depth/Date: 80-130cm - 11/26 through 12/31 Comments: No real new information on the problem other than depths. |
Skied sheltered terrain pushing mid 30s. Avoided wind loaded slopes.