Variable Conditions On South Slopes Above Saddlebag Lake

SNOWPACK OBSERVATION
South Slopes Above Saddlebag Lake
Submission Info
Saturday, January 13, 2018 - 3:00pm
Red Flags: 
Recent loading by new snow, wind, or rain
Rapid warming
South Slopes Above Saddlebag Lake 37° 59' 3.5808" N, 119° 16' 19.5348" W
Snowpit Observations
More detailed information about the snowpack: 

Toured to Dore Pass January 12-13, traveling on flat and south slopes. Crossloading apparent throughout the basin.  Observed 2 small (D1, R1) natural avalanches on northeast slopes that appeared to occur after the 1/10 storm but had since filled in somewhat due to cross loading. Both avalanches appeared to start below rocky cliff and ran <100m. Observed some rollerballing on south and west slopes below rock. While skiing on south slopes up to 11,800, encountered much solar radiation and conditions varied from breakable sun crust to supportable windboard. Boot penetration varied from <1cm to 25cm. Snow on the tioga pass road begins at Warren fork.

On January 12 at 1620 at 10,150, north aspect, 10 degree slope near saddlebag outlet. Slight cloud cover, no precipitation or wind.  -1C air temp, -7C surface tempe -7C, and -5C at 20cm. Boot pen 25cm. Investigated upper layer formation and stability.  Handpite easily failed at 2.5cm and moderate failure at 27cm on facets. Could  not get failure at 40cm, the interface was chunky and not planar.

From the top down:

0-2.5cm  1F windboard

2.5-12cm  F

12-14.5cm 4F

14.5-27cm 4F+

27-31cm 1F

31-40cm F

40-60cm P+

 

On January 13th, skiing south slopes (10-25) from Saddlebag lake to Dore Pass (10,150- 11,800ft). In general conditions were variable from firm windboard over weaker layers to slushier conditions driven by high solar radiation.  Smaller areas of instability persisted (hard over soft) as well a some potential for wet slides. Melt freeze cycle is apparent.

CT test at 11,450, South aspect, 15 slope.  Sky had scattered clouds and no precipitation or wind.  Total snow depth 60cm, boot penetration 12cm.  4C air temp, 0C at surface and -2C at 20cm. CTE (8) Sudden Collapse on facets at 8cm.  No failure at 28cm interface during testing.  When investigated further, interface was chunky.

From the top down:

0-7cm Pencil hard, 1mm rounded grain

7-28cm 4Fingers, Decomposing and fragmented particles, 1mm

28-45cm Knife, melt form 2-3mm

 

 

 

Snowpack photos: 
Weather Observations
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Above Freezing
Precipitation: 
None
Air temperature trend: 
Warming
More detailed information about the weather: 

Warm!
 

ESAC receives support from ...