Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
January 26, 2022
Submitted:
January 27, 2022
Observer:
NWAC Forecaster - Josh Hirshberg
Zone or Region:
East North
Location:
Rainy Pass (2,600-6,300, All aspects)

Signs of Unstable Snow

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

Media/Attachments

Debris from multiple, overlapping wet avalanches, up to size D2.5, that occured roughly between Jan 12-22nd. Below pt 6932 near Rainy Pass
Black Peak NE-SE. Loose (wet and dry) avalanches from roughly Jan 12-20th in the foreground on pt 6963, SE
Debris on Lake Ann from wet avalanches occuring roughly between Jan 12-22nd. Southeast aspect
The track and broken cornices associated with wet avalanche(s) that occured roughly between Jan 12-22nd. Pt 6937, ENE
Debris from multiple, overlapping wet avalanches, up to size D2.5, that occured roughly between Jan 12-22nd.. Below pt 6932 near Rainy Pass
Very large (5cm) surface hoar grains found near Hwy 20, Rainy Pass
Very large (5cm) surface hoar grains found near Hwy 20, Rainy Pass
Very large (5cm) surface hoar grains found near Hwy 20, Rainy Pass
10cm of soft, wind-textured snow remains on the surface from a small storm on Jan 20th. NE, 6150ft, Heather Pass.
A deep crown (center, left under a rock band) and broken cornices from mid-January. 6800-6600ft, ENE, Point 6937, Rainy Pass
Surface Hoar on Hwy 20 near the top of WA Pass.
Numerous wet avalanches from a range of dates betweeen Jan 12-22th. SE-NE, Whistler Mtn and Cutthroat Peak
A very deep crown of a slab avalanche from mid-January. Hanging, unsupported face in the Hairpin valley, NE, 7,300ft. Washington Pass
South aspects of Hinkhouse peak with evidence of drifting from westerly winds since Jan 20th

Advanced Information

Weather Summary

Cloud Cover:
Clear
Wind:
Calm

Strong temperature inversions all day w valley fog in the AM. High, thin clouds built in the PM. The effects of both short and longwave radiation were evident in the variety of surface conditions that we found.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Jan 12, 2022
() 		Rainy Pass, Point 6937
NE 6600ft 		D2.5 HS-Hard Slab 8ft NC-Cornice Fall
A deep crown (center, left under a rock band) and broken cornices from mid-January. 6800-6600ft, ENE, Point 6937, Rainy Pass
Debris from multiple, overlapping wet avalanches, up to size D2.5, that occured roughly between Jan 12-22nd.. Below pt 6932 near Rainy Pass
The track and broken cornices associated with wet avalanche(s) that occured roughly between Jan 12-22nd. Pt 6937, ENE
Debris from multiple, overlapping wet avalanches, up to size D2.5, that occured roughly between Jan 12-22nd. Below pt 6932 near Rainy Pass
Report
1 Jan 12, 2022
() 		Hairpin Valley, Hwy 20
NE 7300ft 		D2.5 HS-Hard Slab 8ft N-Natural
A very deep crown of a slab avalanche from mid-January. Hanging, unsupported face in the Hairpin valley, NE, 7,300ft. Washington Pass
Report
Rainy Pass, Point 6937
Hairpin Valley, Hwy 20

Widespread loose wet avalanches on E-S-W aspects generally to size D2 with a few larger slides or deeper piles that resulted from overlapping avalanches. Most were older and I didn't see any that appeared to have occurred within the past 3 days. It seems the bulk of the activity was with the Jan 12th rain event, tho I saw many examples of more recent wet avalanches. Notable slides including 2 older, deeper slab avalanches, may have involved cornice fall.

Snowpack Observations

We focused on the range of surface conditions. E-S-W slopes that are exposed through the sun have widespread, and sometimes stout crusts. Sunny slopes near Rainy Pass softened during the day above 4,600ft, though it appeared that areas in deep drainages and at lower elevations stayed cold and frozen with temperature inversions.
Under the tree canopy, surfaces were a bone-jarring, "coral-reef" textured melt-freeze crust that stayed frozen solid all day. Near Rainy Pass from 4,600-6,300ft we saw no change with aspect in tight trees. However, the snow in open trees was consistently softer with only a light crust on the surface.
We found surface hoar of different varieties (see photos) along the highway, in valley bottoms, and near lakes and drainages. Some intricately feathered grains exceeded 5cm. Little to none was observed in other terrain or on slopes steep enough to slide.
Shaded, wind-sheltered slopes near and west of Washington Pass are still holding dry snow that initially fell on Jan 20th. At 6,300ft on a NE aspect near Heather Pass, we found 10cm of soft, dry wind rippled snow over a crust. Up to 20cm may exist on similar slopes. These areas, along with many slopes holding just thin crusts, are also building near-surface facets.

pen slopes

Avalanche Problems

No avalanche problems. Travel hazards- slip and fall, challenging snow, etc outweigh avalanche hazards. That said, we made sure not to linger under overhead cornices.

WordPress Lightbox