Professional Observation

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Weather Summary

Anywhere from 8-12" of new snow were observed in protected areas. The storm on the night of 1/4/21 laid in wind slabs up to 6" deep in upper elevation terrain before finishing in a calmer manner. Moderate South and West winds were blowing much of the new snow around in exposed terrain. The fresh morning skin track that I followed up Phat Ridge was filled in in what I would guess was a couple of hours. See photo. Ongoing wind loading was creating shallow wind slabs at ridgelines.

Avalanche Observations

#	Date	Location	Size	Type	Bed Sfc	Depth	Trigger	Comments	Photo
1	Past 24 hours	Dollar Ridge NE 8500	D3	SS				Hard to tell many details, but seemed to probably be 200 meters wide
1	Past 24 hours	Ridgeline separating Middle Fork and South Fork of the Imnaha River E 8000	D3	SS				Hard to tell details, but large avalanche on NE aspect

Snowpack Observations

We are dealing with a complex snowpack in the Northern Wallowas. It might be a bit before we are out of the woods on this one.... Average height of snow around 8,000 feet in the wing ridge area was 48"/120 cm. There was a nice layer of 2 inches of light density snow that fell straight down from the sky at the end of the storm with little wind affect. This snow was covering up a more dense, wind affected layer of snow. In many areas the new snow felt inverted or upside down as your ski would seemingly be supported by this stiffer wind slab, only to break through to lighter density snow below. When digging deeper in the snowpack, on both a NW and SW aspect, a 1F hard slab was present above the Solstice Rain Crust and associated crust jarble. The SRC found to be a little over 2 feet deep (70cm). Below the crust, very weak faceted snow (F-4F hard) existed. We found consistent snowpack test results showing clean easy shears in both the new snow, and in the deeper persistent weak layers. See Photos below and recent video. Although we did not get propagation on the ECT, I certainly wouldn't use that data for decision making to step into more aggressive terrain. Perhaps it indicates that the 1F hard slab is making it harder to impact the SRC and associated weak snow. I always use snowpack tests as data points, not as decision making tools (unless it's helping me decide to turn around!!).

Avalanche Problems

Problem	Location	Distribution	Sensitivity	Size	Comments
Wind Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: up to 12" from 1/4/21
Persistent Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: up to 3 feet deep, below SRC into old november facets

Given the structure of the snowpack in this area, there is definitely potential for a smaller avalanche such as a windslab to produce enough weight to "step down" into the older snow and create a much deeper, more destructive avalanche.

Terrain Use

We did not step out onto any terrain that was steeper than 35 degrees. We utilized subridges and high terrain to manage our uncertainty within the snowpack. We avoided steep leeward and windloaded terrain. If we got pushed into smaller terrain features (convex rollovers), we slowed down our travel and managed them one at a time with eyes on.