Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 21, 2022
Submitted:
February 21, 2022
Observer:
NWAC Forecaster - Andy Harrington
Zone or Region:
Snoqualmie Pass
Location:
Snow Lake Divide

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

A small crown on a rocky unsupported slope in the Alpental Valley
Dry Loose avalanches were found to have initiated near rocks and trees. Some were solar induced
The 2/19 interface was found 20 inches down from the surface with the Valentine's Day Crust a few inches below that.
Small slabs were spotted on most convex or rocky slopes in the Alpental Valley. At upper elevations, debris piles may have been from loose or slab avalanches.

Advanced Information

Weather Summary

New/Recent Snowfall:
20" HST over the 2/19 @ ~4400'

Snow showers on the drive up to the pass gave way to sunshine for most of the morning in the Alpental Valley. The East flow and low clouds slowly made their way up the valley and were obscuring skies around the time we left the field at noon. WInds were calm.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
15 Feb 20, 2022
() 		Alpental Valley
E ft 		D1 SS-Soft Slab N-Natural
Small slabs were spotted on most convex or rocky slopes in the Alpental Valley. At upper elevations, debris piles may have been from loose or slab avalanches.
A small crown on a rocky unsupported slope in the Alpental Valley
Report
Alpental Valley

Looking around the Alpental Valley on our approach, we could spot a shallow crown on almost every steep or unsupported slope between Mushroom and the Divide. On slopes that see direct sunshine at upper elevations, there were debris piles below the rock bands, hard to tell if they were slabs or loose avalanches. Also spotted a number of dry loose avalanches during our time out on a variety of aspects. Many were solar induced when chunks of snow shed from trees or rocks.

Snowpack Observations

The snowpack was similar to what I found on Kendall yesterday, but a bit deeper. The 2/19 interface was found 20" (51cm) below the surface and the V. Day crust was 23" (59cm) down. Hand shears and small column tests again produced failures just above the 2/19 interface, and weak snow was found just above the V. Day Crust. A layer of rimed precipitation particles was found 16" (40cm) down and was reactive in small column tests with one test producing a sudden collapse. That said, using test slopes and watching people ski burlier lines than me, I did not notice many human-triggered avalanches on these layers. Snow was fairly light but did have some slab character to it. On the ski back to the car down, the apron above Source Lake had developed the slightest sun crust on the surface.

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