Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
March 20, 2022
Submitted:
March 21, 2022
Observer:
NWAC Forecaster - Irene Henninger, Jason Speer, Ryan Kitchen
Zone or Region:
West North
Location:
Excelsior (All aspects 2700-5500ft)

Signs of Unstable Snow

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

Media/Attachments

We found several shallow storm snow breaks in a compression test with moderate taps on the south facing pit.
A right side up 50cm of the snowpack led to the combined March 8 and early March knife hard crusts midway down the pit.
The top 120cm of this pit were mainly right side up. Just above the knife hard (late Jan) crust was a 20cm layer of rounding facets which were pencil hard.
Unsure how to test small slopes without skis or sledding out onto it, I resorted to bellyflopping onto this small cornice. This untested method is not appropriate for large slopes, larger cornices, or anywhere that you might suspect an avalanche to entrain snow. I didn't get a result from it. A north-facing slope at 5400ft.
A large, east-facing cornice along the ridgeline in the Excelsior area.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Wind:
Calm

Cloud ceiling was about at 5800ft all day, keeping views limited. About 6 inches of low density snow fell last night, and it was minimally wind-affected where we traveled, aside from minor cornice re-distributions along ridgelines. Occasional light SW wind was noted. Light snow began around noon.

The Excelsior Basin was extensively ridden and no signs of old avalanches were seen, and we did not see or trigger any new avalanches.

We heard one report of a large natural avalanche on the neighboring Bearpaw Mtn, failing in a rocky chute near the top of the mountain on a northeast aspect, which probably occurred Saturday.

Snowpack Observations

We found a right-side-up snowpack with good riding in the Excelsior basin at 5100-5500ft. The March 8 crust (or harder snow layer) was noticeable about 2 feet down in some spots near the bottom of the basin.

In pit tests we found several storm snow layers failing on moderate compression taps, and failing but not propagating in an extended column test, in the top foot of snow.

Snow heights were around 400cm in the basin. At 3500ft the snow was a variable 150cm in clearings, but by that elevation a lot of the snow was melted out beneath trees. About 3000ft is where the snowline was from the previous night. In the afternoon, snowmelt which occurred during the day was very noticeable from that elevation down.

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