Date of Observation: 03/18/2023
Name: Zach Guy
Zone: Southeast Mountains
Route Description: Traveled on all aspects of Mt. CB to 11,800 to observe current snow surfaces ahead of the next storm.
Observed avalanche activity: Yes
Avalanches: Had good views with binoculars of a lot of terrain. Nothing notable from the past few days; some small loose avalanches and recent cornice fall/wind slab activity off of Owen that looked to be about D1.5 in size.
Weather: Notable 30-degree diurnal swing at Butte SNOTEL past 36 hours with temps dropping to near zero overnight, and highs near freezing. Light winds, clear skies.
Snowpack: The current snow surface is the most widespread and notable near-surface faceting event I’ve observed this spring, which will spell trouble for the upcoming storm. The combination of low-density snow at the tail of the last storm, light winds, and big temperature swings the last few days have promoted faceting in the upper few cm’s of the snowpack. Today’s cool temps and strong March solar were ideal for radiation recrystallization. I found 1cm of dry, faceting grains above thin crusts (1 to 3 cm) on east, south, and west aspects, grain sizes about 1mm in size. Northerly aspects held cohesionless facets, ~1mm. I suspect only the lowest elevation southerlies got warm enough to cook off, but I didn’t verify that.
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- West aspect, 10,000′, 35 degree slope. 1cm of radiation recrystallization above a crust.
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- South aspect, 11,800′, 30 degrees. 1cm of radiation recrystallization above a crust.
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- East aspect, 11,800′, 35 degrees. 1cm of radiation recrystallization above a crust.
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- North aspect, 11,500′. Small-grained near surface facets.
