Hemlock Ridge to the Highway

Observer: d lewis
Loc: Hemlock Ridge
Lat/Lon:37.7433, -119.1024
Elevation: 10100 f
Aspect: NNE Angle: 34°
Signs of Instability: Recent Avalanches, Wind Loading
Sky Cover: FEW
Precipitation: No Precipitation
Wind Speed: Moderate, beaufort
Wind Direction: SW
Blowing Snow: Intense SW
Snow Depth: 311cm
New Snow Storm:115cm 
Boot Penetration: 45cm 

Stability Tests: CT21 Q2 75cm CT14 Q2 75cm ECTN21 Q2 94cm Partial collapse under shovel CT12 Q2 94cm CT11 Q2 94cm

Comments:

 Toured from June Mountain over to the base of San Joaquin mountain to assess recent avalanche activity and new snow stability. Noted two recent natural Wind Slab failures from today (3/23) as well as one or possibly two D3. A D3 under 3D chute. On Dream Peak noted D3, further along the ridge another D3 just north of the Dream Peak cirque. As I climbed up through the trees to gain Hemlock ridge saw signs that Hemlock trees avalanched during the last big cycle (3/21-22). Summited the ridge and was able to look into Fern Creek and the east side of Carson Peak. Saw two D3’s and evidence of 3 D2’s. Saw a good size debris field on the apron of Mt. Wood D3+ Northeast aspect, ran approx. 2000’ vertical. Looked to be a Wind Slab from today (3/23) or late during the cycle (3/21-22)  

Snow stability tests suggested a weakness 14 cm down from the surface with moderate failures. Hand shears showed similar results. Had a couple of other failures but unable to duplicate consistently. Extended column tests were negative, failed directly under the shovel but didn’t propagate. No collapsing or whoomfing noted throughout. Snow was more supportive on the approach to San Joaquin mountain above 9200’. As you dropped down below 9200’ and wrapped around the mountain, the snow became more unconsolidated and punchy with thin Wind Slabs peeling off the surface on open or semi open slopes above ~9500’ The new snow above ~8800’ was dry and varied in depth from ~100cm to 125cm. Below it quickly decreased in depth and by 7500’ it was only a few cm. The snow below~8500’ was only 10 to 15 cm new over semi-supportive breakable crust. Should freeze-up stronger overnight and at least become fully supportive while frozen. Slopes receiving any direct sun beginning to become moist and forming a thin melt freeze crust once cooled. Also was able to get some of the wet surface snow to peel off on steeper slopes, possible Loose Wet hazard, especially with further warming.   

Strong SW winds and plenty of transportable snow were loading NW-N-NE aspects of all the peaks visible from Mammoth to Tioga Pass. Mt Wood was a real standout with large extended snow plumes. With some impressive downslope winds and snow banners down to ~8500’.