Observation: NWAC Observer

All Observations

Basic Information

Observation Details

Observation Date:
March 5, 2022
Submitted:
March 5, 2022
Observer:
NWAC Observer - Drew Lovell
Zone or Region:
East Central
Location:
Railroad Creek Valley (W-N-ESE, 3000'-8300')

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced

Media/Attachments

Debris from sz.3 Storm Slab, thinly buried in 5-10cm low-density snow. This avalanche ran over 3000' to the valley bottom, where the deposit looked more like a large wet-loose event.
Small wet loose slides from Mar.5, overrunning remnant crowns and debris from Feb.28.

Advanced Information

Weather Summary

Cloud Cover:
Clear
Temperature:
25°F
Wind:
Calm
New/Recent Snowfall:
80-120cm settled HST above Feb.26 interface, capped with 10cm low density from Mar.3. Below approx.5500'-5000', the most-recent low-density HST decreases and overlies hard, slick rain crust.

Another beautiful day. We were expecting to find some wind-effect in the alpine, but found very little. We were surprised by how cold we felt in the shade, in contrast to slopes baking in the strong sun.

Very widespread evidence of the Feb.28th avalanche cycle, seemingly on all aspects. As in other areas, most crowns from mid-storm are obscured, but debris is very evident. Activity seemed to consist of Storm Slabs or Wet Loose (or some hybrid of the two) up to sz.3. Debris ranges from rock-hard and treacherous to soft and very skiable, with up to 40cm over top in the alpine.
Small wet loose to sz.1 observed today, on Mar.5.
Most noteworthy pertinent negative is the apparent absence of deep slab activity. With excellent visibility, we have yet to observe any crowns that would point to failure at a deeply buried persistent weak layer.

Snowpack Observations

Firm and fast travel below treeline. A trace of more-recent low-density snow from around Mar.3 deepens to 5-10cm by around 5500' and overlies a 5-10cm thick 1F hard temperature crust, which is very edgeable on the up and skis fairly soft on the down. It seemed like rain and or warming occurred locally up to about 5800'-6000'. Above this elevation, cold, dry powder exists, with some wind-texture and surface faceting.
Profiles on northerly aspects at 5800' and 6700' held 100 - 120cm storm snow over a visually discernible interface from Feb.26 (unreactive in tests).
At the upper elevation pit (6700', N) the late January interface had some rounding facets between crusts, down about 150cm. Deep Tap tests were unremarkable. The mid-Feb.interface was down over 130cm and was unreactive.
At the lower pit (5800', NE) we found the mid-Feb. and Late Jan. interfaces to be nearly indistinguishable and down about 100cm. Compression Tests yielded inconsistent results, ranging from moderate sudden collapse to hard break.

A previous profile on a solar slope showed a very strong snowpack, with P-hard melt forms to the ground, capped by crust from the ongoing freeze-thaw cycle.

We experienced only very isolated cracking in windslab of limited extent on the up today.

Avalanche Problems

Problems seem to be limited to small wet loose, given the current regime of strong overnight cooling.

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