Observation: NWAC Observer
Basic Information
Observation Details
Observation Date:
December 13, 2021Submitted:
December 13, 2021Observer:
NWAC Observer - Drew LovellZone or Region:
East NorthLocation:
WA Pass (E - S, 5500'- 7200')Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
None ExperiencedAdvanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
18°FWind:
Light , SENew/Recent Snowfall:
15cm HN at Silver Star in AM, 20-35cm HST at Pass and throughout ski terrainA poor visibility day. Generally obscured with on and off s-1, light SE winds and minimal transport. It is worth noting that snowfall intensities seemed greater further east along the Hwy 20 corridor and in the valley.
No new avalanches observed
Snowpack Observations
The Early December Crust was down 70 - 130cm in terrain observed today. Cooling and ongoing settlement have improved both ski quality and travel conditions. Ski pen was a squishy 30cm over a ski-supportable transition from F to 4F- snow.
A test pit on a SE aspect at 6500' showed an HS of 200cm. The Early Dec. Crust was down 115cm in this location. Compression and Deep Tap Tests both yielded Hard Breaks, above or at the crust interface. One could generate some Moderate Resistant Planar shears within the most recent storm snow, which were not cause for concern due to very low density.
Ski testing on steep, unsupported features between 6000'-7000' yielded only minor sluffing.
Tree wells are vacuous and gaining depth. Creek holes are abundant and worthy of avoidance.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
Layer Depth/Date: 10-20cm Comments: No windslab observed today, but suspect that it exists in the local alpine terrain. |
The ongoing settlement, cooling, and recent low-density storm snow have created a favorable density profile above the Early December Crust. While minimal faceting was observed at this interface in our field location, more information and tests are needed.
Another party in the same area experienced a large collapse on a south facing slope between 5500-6000'.
We experienced no wind slab problems today, but suspect that slabs from previous SW winds may exist in the local alpine terrain, now veiled by more recent low-density storm snow.