Yost Lake, Four Seasons Trees

Yost Lake, Four Seasons Trees
Submission Info
Friday, March 16, 2018 - 2:45pm
Red Flags: 
Recent loading by new snow, wind, or rain
Yost Lake, Four Seasons Trees 37° 45' 7.56" N, 119° 6' 25.56" W
Snowpit Observations
More detailed information about the snowpack: 

_Observer: d lewis
Date: Mar 16, 2018, 9:46 PM
Loc: Yost Lake, Four Seasons Trees
Lat/Lon:37.7521, -119.1071
Elevation: 8127 f
Aspect: N Angle: 37°
Signs of Instability: Shooting Cracks, Wind Loading
Sky Cover: OVC
Precipitation: Snow, Moderate snowfall - 2 cm/hour
Wind Speed: Light, subjective
Wind Direction: SW
Current Temp:-5 to -10°C Trend:➘
Blowing Snow: Light
New Snow 24-Hours:50cm Storm:60cm 
Boot Penetration: 40cm
Snow Stability: Fair
Stability on similar slopes: Fair
Avalanche Danger: Considerable

Comments: 3 Stability Tests: CT4 Q2 21cm CT1 Q2 21cm, CTN. 4 Snow Pit Layers, Measured bottom up Top Location: 135. Test produced mixed results. Upper 20 cm shows hints of a slab over loose Fist-. Ski cuts on 35 + degree test slopes resulted in small 10' slab releases that continued down slope eroding into the new snow. D1 Most of the snow from the valley bottom to 9000' from the March 1-3 storm. From the Four Seasons (elev.7400') to the water tank 12" to 18" (30 cm to 45cm) base with lots of sage and brush mixed in. New snow 4" to 8" (10 to 20 cm). All lumps and bumps should be treated with suspicion. From the water tank (elev. ~7600') to ~9000' good supportable coverage. Not overly deep, so rocks, stumps, and downfall are a concern. New Snow varied from 30 cm at the water tanks to 60 cm near 9000'. Overall snowpack depths: 1' to 2' for 7600' to 8500', 9000' ~150 cm (~60”) . Prior to the early March storm, little snow on the ground, ~4” (~10cm), which formed into Depth Hoar. Stability test shoed the new snow was too loose for large slab failures but localized releases possible on steeper terrain, 35 degrees and steeper. Road closure on 395 for over an hour due to incident on return to Mammoth.  

Snowpit or crown profile photo or graph: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Greater than 1 in. per hour
More detailed information about the weather: 

Snowing mostly 1" an hour with periods of ~2" an hour, which formed the subtle slabs near snowpack surface. Winds generally light SW with ocaasional gust, Briek periods of moderate. 

-- placeholder --

ESAC receives significant financial support from ...