Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
January 18, 2023
Submitted:
January 18, 2023
Observer:
NWAC Forecaster - Andy Harrington
Zone or Region:
West South
Location:
Bullion Basin

Signs of Unstable Snow

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

Media/Attachments

This sensitive cornice triggered a small wind pocket on the slope below when kicked. The cornice was already rebuilding again 45 minutes later.
Actively blowing snow and sharp new cornices were visual clues available to help identify wind-loaded slopes.
Snow profile in the Bullion Basin area. A variety of atmospheric river crusts and snow with different levels of moisture content were observed. The newest snow was poorly bonded as was the snow to the 1/14 MLK crust.

Advanced Information

Weather Summary

New/Recent Snowfall:
3-4"

Snowing all morning, moderate at times. Likewise, it was blowing all morning with mostly moderate winds in my location.

No new natural avalanches were observed, but visibility was poor. I was able to kick some cornices to get a few pockets of Wind Slab to fail. During my descents, I was able to get some snow moving fast and medium-ish far on the 1/14 crust.

Snowpack Observations

Took a walk up into Bullion Basin and made two laps off Bullion Peak. There was around 3-4" HN poorly bonded to this past weekend's snow sitting atop the 1/14 interface. It appeared that a layer of stellars was providing the poor bond, so I expect this interface to heal up relatively quickly. It was easily failing in small column tests and hand pits. Other midstorm layers from over the weekend showed some inconsistent failures, but more consistent breaks were found just above the 1/14 MLK crust. This would be the layer of interest that I would target moving forward. It failed on isolation when doing a tilt test and failed repeatedly in shovel shear tests and hand pits, albeit a bit resistant with the hand shears. During small column tests, it generally failed +1 or beyond the standard recording. I found generally around a foot (~28cm) of snow over the MLK crust at mid to upper elevations except in wind-loaded areas where it was obviously a bit deeper. Conversely, it was much shallower or even on the surface in wind-stripped areas near ridgelines. I would categorize the bond somewhere between moderate and poor.

Speaking of ridgelines, cornices were actively building with blowing snow and were sensitive when kicked or in some cases traveled next to. As stated above, pockets of Wind Slab failed in a few locations when kicking cornices. One of these cornices was half rebuilt by the time I came up for a second lap 45mins to an hour later and my skin track along the ridge drifted in from blowing snow during the same timeframe.

While deep tap tests on the Christmas Crust did not produce any results, I did have two fairly planar failures while messing around in the pit. Not saying it's a problem, but I'll throw it in the back of my mind for now.