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Observation: Pink Pine

Observation Date
12/29/2022
Observer Name
Zimmerman-Wall/Hogg
Region
Salt Lake » Little Cottonwood Canyon » White Pine » Pink Pine
Location Name or Route
Pink Pine
Weather
Sky
Scattered
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Started cold and clear, ended cool with high cloud. Temps below freezing but not uncomfortable. Convective clouds built throughout mid day and then burned off by afternoon. No new snow, light northwesterly winds but not moving snow around at mid and lower elevations. Some ridgeline transport visible early.
Snow Characteristics
New Snow Depth
14"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments
Storm snow slow to settle and riding conditions remain all time. In the afternoon the west and south took a little heat and may sport a faint zipper tomorrow, maybe.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
We know the structure is there. But the red flags were not in your face today in the terrain traveled. That being said, just across the range it was a very different story. The spatial variability we are seeing right now is apparent and it still seems that steep and wind affected polar aspects are not to be trusted.
Avalanche Problem #1
Problem
New Snow
Trend
Same
Problem #1 Comments
Few long running loose drys up on the steep south facing shots (White Pine Chutes and Little Pine) but nothing with slab characteristics. Lots of ski traffic over there with no results to speak of.
Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #2 Comments
I am convinced there could be another developing PWL in the mix somewhere closer to the surface. It seems that we might have developed a thin layer of Surface Hoar and Near Surface Facets in the brief interlude of clear weather after the historic wind event of the evening of 12/21-morning of 12/22. This then got capped and preserved by a trace of light density snow followed by the rime event of Christmas weekend, followed by the most recent 1-2 feet. The recent avalanches noted in Cardiff, Mineral on 12/28 and the big slide in Dutch's today don't seem to be deep enough to be the 11/28 layer we have been tracking. Maybe I am wrong. If I am please tell me and I will go back to believing we only have one PWL. I think the slab character is the wild card. In places like Pink Pine the slab is F trending to 4F (soft). But in areas impacted by wind, this could be 4F to 1F (trending towards hard) which would explain the wider propagation witnessed.
Comments
I performed back to back ECTs in the same location along the Pink Pine ridge at 8600' ENE facing. This was in a sheltered location and I got an ECTP 21 and and ECTN 25. Along with a STH all on a layer of 2-3mm surface hoar capped by a bit of low density decomposing stellar snowflakes down about 55cm. You could see this line in the test wall, but it really stuck out in the three tests. This didn't jive with what I was expecting, and the slab was so soft I was not getting any signs of instability in the area. I skied an adjacent slope with similar terrain characteristics after several hard ski cuts with no results. Slope angle was 30-35 degrees, but only for a 100-200 feet before slackening.
Along the west facing terrain of lower White Pine (West Scotties) we noted a crust below the new snow, but it was not stout and provided more rebound when you hit it than expected. Down deeper, you could find some weakness around 90cm, but did not do a full investigation.
Photos:
1. Pink Pine terrain where surface hoar found
2. ECTP result
3. Failure layer (SH and DF)
4. Upper White Pine mid afternoon.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
None
Coordinates