Black Mtn, Red Lake Bowl - New Snow, Wind Loading, Mid-pack Weaknesses

SNOWPACK OBSERVATION Black Mtn, Red Lake Bowl Virginia Creek
Submission Info Forecaster Friday, February 23, 2018 - 2:45pm

Contributor

d lewis

Red Flags:

Recent loading by new snow, wind, or rain

Obvious avalanche path

Black Mtn, Red Lake Bowl 38° 2' 23.784" N, 119° 16' 0.768" W

See map: Google Maps

Snowpit Observations

More detailed information about the snowpack:

Observer: d lewis
Loc: Black Mountain, Red Lake Bowl
Lat/Lon:39.0399, -119.2669
Elevation: 10400 f
Aspect: NNE Angle: 24°
Signs of Instability: Wind Loading
Sky Cover: BKN
Precipitation: Snow, Very light snowfall < .5 cm/hour
Wind Speed: Light, subjective
Wind Direction: E
Current Temp:-14°C
Blowing Snow: Moderate NE
Snow Depth: 101cm
Snow Temperature 20cm: -13° C
Boot Penetration: 10cm

Comments: Toured up to Black Mtn to assess the new snow stability. Initially, minimal E-NE winds, increasing to Moderate in the PM. Air temp -10 to -13.8. 1-3" new low density snow w/ minimal wind effect, pretty evenly distributed. Wind was initially light & variable but increased in the PM to Light to Moderate, Easterly to Northeasterly near treeline and Moderate to Strong in the Alpine with moderated to severe wind loading on SE-S-SW-W-NW in the alpine. Light wind loading treeline and below with gusts. Thin slab forming (2-4cm) on top with minimal slab character below within the new snow. Stability tests mixed results, suggest isolated stubborn wind slabs over facets or loose new snow with failures of moderate to hard, Q2 to Q3. 2 Stability Tests: ECTP11 Q3 78cm CT21 Q2 78cm. Suspended older Wind Slabs are stubborn in nature but can be triggered with sufficient load or from a weaker thin spot that propagates to where the slab is deeper.

Snowpit or crown profile photo or graph:

Snowpack photos:

Weather Observations

Blowing Snow:

Yes

Cloud Cover:

50% of the sky covered by clouds

Air temperature:

Below Freezing

Wind Speed:

Light

Precipitation:

Snow

Air temperature trend:

Cooling

Wind Direction:

Northeast

Accumulation rate:

Less than 1 in. per hour

More detailed information about the weather:

Snow flurries with scattered clouds. Initially, light winds aloft but increased throughout the afternoon. By late afternoon, winds had increased to moderate to strong in the Alpine, low to moderate treeline and below. Snow transport in the Alpine moderate to intense in the late afternoon. Treeline and below, light transport with gusts.