Buttermilk Country-Mt Tom- East Gully - snow conditions

SNOWPACK OBSERVATION
Mt. Tom East Gully
Submission Info
Forecaster
Friday, January 24, 2020 - 11:30am
East Gully Mt Tom 37° 20' 42.0828" N, 118° 39' 5.2704" W
Snowpit Observations
More detailed information about the snowpack: 

Put the little 4cyl into 4low and bashed my way up the Horton creek Rd up beneath the East Gully of Mt Tom. Had to hike for a bit and then was able to skin at 7000ft on very thin conditions following a nice 6point mule deer up the gully. Quite warm, felt like spring and the snow down low was already getting moist and soft at 900am. A bit of snow blowing around at ridge top, but winds dissipated by noon and for the most part was dead calm on the eastside of the mountain today. Did not observe any loose wet signs on the sunny aspects today. Minor collapses of snowpack in very thin coverage in lower vegetated terrain. No other signs of instability noted.

31F @ 9400ft @ 1030am

28F @ 11700 @ 200pm

24F @ 11800 @230pm

Multiple people have reported observing audible collapsing of the snowpack and it’s no surprise as the lower elevations are composed of relatively shallow and structurally weak snow. I dug a shallow 55cm snow pit at 9400ft on an East Aspect and found what I’d term as a shot sandwich of multiple crusts and faceting snow layers.  This was located on what I call the “pyramid” a prominent pyramidal moraine feature that lies in the middle of the East Gully. Although stability tests really didn’t show easy results or super unstable conditions, the relative sandwich of melt-freeze crusts, faceting snow and in some places firmer overlying wind slabs gives cause for concern.  At least on Mt. Tom and much of the mountains near Bishop there is not much, if any, contiguous snowfields anywhere. Most snow fields are bisected by shallow reefs, vegetation, outcroppings, or completely windswept zones. So big connected slabs are not very common, if at all, especially down low.

For the most part the only contiguous snowfields are in the upper cirques at higher elevations and "generally" the snow up there has more right side up properties than compared to lower elevations...but not everywhere as we are finding out. Easily propagating wind board over crust/facet combos has been found up high at ~11,000ft, E aspects, particularly in the Baldwin cirque area (McGee creek/Crowley area). On Mt Tom today at 11,800 E aspect, I got a hard result, but sudden collapse on my ECT test, (ECTP27) 50cm below the surface on a faceted layer. There was not a planar interface at the propagation, but a rough break within loose faceted rounds. From my recent travels, one thing is certain that one pit anywhere is not going to give you the full picture. The spatial variability of the snowpack is tremendous right now, and I found varying conditions throughout the upper cirque through probing and digging. Hand pits up on N-E apects up high showed anywhere from 15-25cm of soft powder that was very well bonded to underlying surfaces. 

It will be interesting to see how this shallow snowpack will react if we ever do get a typical big sierra dump with several inches of SWE (Snow Water Equivalent). I imagine we could see the aftermath of a good avalanche cycle.

Surface conditions were relatively very soft and provided fantastic skiing from 11800 all the way down to the top of the Pyramid moraine at 9800. Thin conditions with breakable crust existed from there on down, but with the solar input and warming it wasn’t too bad.

I Posted 3 videos of locations I dug in today to show the variability through elevation and the lower elevations compared to the upper...

1) 9400ft       2)11700ft         3) 11800ft       all on East aspects today

Snowpack photos: 
Snowpit videos (tests, etc): 
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