Date of Observation: 11/12/2021
Name: Eric Murrow
Zone: Northwest Mountains
Route Description: Poverty Gulch underneath sunny side of Mineral Point over towards Angel Pass
Observed avalanche activity: Yes
Avalanches: Observed one recent natural avalanche below the summit of Augusta. Big enough to carry but not bury a person.
Weather: Strong winds in the morning relentlessly transported and stiffened snow near and above treeline. Winds subdued some in the afternoon. East and southeast aspects appeared to receive the most continued loading.
Snowpack: We ascended terrain facing southeast through east through northeast to 11,900′. Storm totals reached up to ~18″ near treeline (hard to measure as all terrain traveled was open and heavily affected by the wind). Dug a test profile on a drifted southeast feature at 11,000 feet with 3 feet of drifted snow resting on a melt/freeze crust without any result. A test profile on a north feature at 11,900′ showed moderate propagating results at the new/old interface which consisted of 1mm facets (see image). The slab was around 50cm thick and 4finger hard. Immediately following the test profile the slope collapsed as we walked away. These test results and signs of instability steered us towards safer, lower angled options.
We moved through many drifted features that faced east and southeast looking for Wind Slab formation and found two locations that shot cracks up to 75 feet. The most reactive places were generally the stiffest and most supportive drifts.
Photos:
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- Shooting crack in a east slope at 11,800 feet. This drifted snow surface was very stiff.
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- Test Profile from north feature showing propagating results where storm snow rests on faceted grains. This structure appeared to be common across northerly terrain at upper elevations in the Ruby Range area.
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- Recent Wind Slab avalanche on south east aspect of Augusta Mountain.
