Shooting cracks on Baldy

CBAC 2020-21 Observations

Zone: Northwest Mountains

Location: Mt. Baldy: Quigley Creek

Date of Observation: 11/21/2020

Name: Zach Guy

 

Subject: Shooting cracks on Baldy

Aspect: North

Elevation: 9,600 – 11,800′

Avalanches:

Skier triggered several harmless sluffs in the new snow that ran about 400′ on shady aspects. A couple similar naturals on Baldy.

Weather: Bands of convective clouds and showers through the day. A few pulses of very light (S-1) graupel. Overcast to scattered to overcast skies. Light westerly winds, brief periods of light wind drifting off of high peaks.

Snowpack: We went hunting for persistent slab feedback on north-facing terrain near treeline. After several unexciting stability tests and a number of hand pits or surface obs that showed the structure was lacking (missing a slab or missing a weak layer), we had all but given up on finding any good feedback. As we were exiting a steep cut bank above a creek at 10,800′, we got three collapses and shooting cracks up to 75′, failing on the Nov 6 facet layer (2 mm, fist hard). The slopes were easily steep enough to slide, but held in place, perhaps from ground roughness?
No other signs of instability through the day apart from shallow sluffing. 3″ to 5″ of new snow. The snow moistened on southerly aspects, where the storm interface is a 1F melt-freeze crust. At lower elevations, shady aspects, the snowpack is about a foot deep: .5mm moist, rounding facets (F+ to 4F-). Gaining elevation, the snowpack transitions to dry, 4F and more rounded, along with a significant amount of previous wind scouring at upper elevations. See photos and profile.

Photos: