Mt Aggie -Snow Conditions -Warming Southerlies and Poor structure on E aspects

SNOWPACK OBSERVATION
SE side Mt Aggie
Submission Info
Forecaster
Tuesday, January 28, 2020 - 12:15pm
Mt aggie 37° 32' 54.4344" N, 118° 50' 16.1736" W
Snowpit Observations
More detailed information about the snowpack: 

Headed up McGee Creek canyon and up Mt Aggie from its SE side today to check warming conditions and how our persistent slab problem is faring. There were some swirling winds and spindrift activity at the 11000ft level and sporadic thin cloud banks that moved through during the early hours of the day. South aspects were already warming and softening by 10am, and there were signs of previous rollerball activity from Monday’s heat loosening the light Sunday snowfall. There was no active loose wet activity today where we traveled; most snow on southerly aspects was cooked down already and we didn’t observe anything additional moving from sun effects. There was evidence of a slab avalanche that had run 800ft or so during the January 16th storm that had reached the main gully we ascended.

Snow depths within the SE gully and S aspects were shallow with 10-40cm of consolidated melt/freeze effected snow. Where not roller-balled out, southerlies were smooth, supportable and provided good surface conditions at 100pm.

We also traveled up an east aspect and found very hollow and incredibly variable conditions with snow depths ranging from 30cm to 90cm. For the most part much of the snowpack here was unconsolidated, punchy and hollow feeling. Did not observe any collapsing or cracking though as we travelled up and down it.

Dug a pit at 10840ft on 100deg E aspect 35deg slope. (SEE ATTACHED PROFILE)

On Stability tests (CT and ECT) we got varying results, but the common thread was they all failed on a shallow melt/freeze crust 5cm below the surface and at 25cm below the surface on a layer of faceted snow beneath the Jan 16th slab.

Both CTs failed on isolation on the shallow melt/freeze 5cm below the surface.

CT15 @ 60cm Q1     &    CT22 @ 60cm Q1

ECTP15 @ 60cm     &     ECTN22 @ 60cm

From stability tests in this pit it would appear that the snowpack has poor instability and it could be assessed as such. On the other hand there were no other signs of instability in the area such as collapsing or shooting cracks or any avalanche activity since the storm nearly two weeks ago. Another factor is that the snowpack is so variable that a pit dug 5meters to either side would have likely shown a different stratigraphy and results with stability tests. While much of our degrading snowpack has bad structure, it does not have contiguous slab across slopes or currently show much, if any, energy to initiate an avalanche.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 
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