Observation: NWAC Observer

All Observations

Basic Information

Observation Details

Observation Date:
December 20, 2022
Submitted:
December 20, 2022
Observer:
NWAC Observer - Brooke Maushund & Katie Warren
Zone or Region:
East Central
Location:
Blewett Pass Area (NE 5300')

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
None Experienced

Media/Attachments

A surface instability likely triggered by a tree bomb
Blowing snow filled in our skin track by the time we came back down
Small surface storm cohesion present, but in isolated areas.
Small surface instability in new snow.
11/22 faceted crystals have now become depth hoar.
Windy weather and blowing snow (worse than visible in photo!) were the theme for the day
https://youtu.be/rjcsvu45dls

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
<32°F
Wind:
Moderate , N
New/Recent Snowfall:
HN 8cm / HST 11cm

•Wind hovered between light and moderate out of the N throughout the day
•Large amounts of snow were available for transport, and wind drifting was evident on features
•Precip rate ramped up from S1+ to S2 throughout the morning into the afternoon

While testing for instability and reactivity, we were only able to trigger very small (D.5-1) wind slabs in isolated areas.

Snowpack Observations

With the total height of snow being 72cm, the snowpack structure is full of facets in the Blewett area. From top to bottom:
•8cm of fresh snow lay on the surface
•Some buried surface hoar remains, mixed in with other stronger grain types
•The old crusts from early December are healing and dissolving, but still present for now
•The 11/22 facets that have been located at the bottom of snowpack for some time now are starting to resemble depth hoar (see photo)

While our stability test results didn't show signs of propagation, we still did not travel on steep terrain due to concerns over this snowpack structure/persistent slab problem in the forecast

Avalanche Problems

We observed the potential and small signs of dry loose and wind slab problems.