Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
April 15, 2022
Submitted:
April 15, 2022
Observer:
NWAC Forecaster - Katie Warren
Zone or Region:
East Central
Location:
Blewett Pass (3900-5500ft; Primarily Northern Aspects)

Signs of Unstable Snow

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

Media/Attachments

What a difference a week can make! I took a walk on 4/8 in trail runners on this road, and now on 4/15 I went back and found just over 2 feet of snow at the trailhead.
Settlement cones around bushes and small trees.
Difficult to discern, these are old wind drifts behind the trees. Recently covered by around 1 foot of new snow.
A favorable hardness profile exists in the 3 feet of storm snow that has fallen in the Blewett Pass area since 4/8/2022.
Large graupel particles fell during peak precipitation.
2 inches of snow fell in only an hour on Blewett Pass today.

Advanced Information

Weather Summary

Wind:
Calm
New/Recent Snowfall:
HST (4/11-4/15): 80cm

What started as a bluebird morning quickly became stormy, and 5cm of snow accumulated in just over two hours. As the afternoon continued, there were additional sun breaks. Winds were calm.

Snowpack Observations

I found 75cm of snow at the trailhead for Tronson Meadows, where just a week ago, it was bare dirt. This storm was quite the treat for the eastern Cascades, where it felt like Spring had arrived too soon. A thin melt-freeze crust has already formed on the surface in some more western and southern aspects. Northerly aspects had cold, dry snow.

At 5000ft on a north aspect, I found an HS of 155cm with 95cm of snow from 4/8-4/15 and a favorable hardness profile. Interspersed in the lower 15cm of this snow was a few thin melt-freeze crusts. While some snow between those crusts was weaker, I could not identify faceted grains and the layers were not reactive in stability tests (CTN, ECTX).

I did locate some older wind slabs covered by more recent snow. While they were difficult to pick out, I could feel the stiffer snow collapse just beneath my skis as I broke trail. I did not see any shooting cracks or feel loud or large whumps in these wind-loaded pockets. These slabs were thin at this location, well below the ridge, around 10-15cm.

WordPress Lightbox