TJ Bowl

TJ Bowl
Submission Info
Monday, January 11, 2016 - 2:30pm
Red Flags: 
Recent loading by new snow, wind, or rain
37° 34' 42.3444" N, 119° 0' 42.4296" W
Snowpit Observations
More detailed information about the snowpack: 

Toured from Tamarack up to TJ Bowl and up above to ridgetop.  Mid to lower elevations had protected unconsolidated snow, exposed higher elevation slopes have been very wind effected and have very variable surfaces, from areas with firm wind board, to zipper crusts, to pencil hard several inch thick breakable crust, but most commonly a slightly denser upper few inches of snow.  Snow surface would change greatly over short spans of 10-20 feet.  Many hand shear tests were done, and as expected results varied widely.  Areas with relatively new windslab 0.5-4 inches thick typically failed easily and cleanily, but it was very rare to find such a reactive area that spanned for more than 10-20 ft wide.  Some handshears did not fail at all.  In newer/thinner wind slabed areas, switchbacks in the skin track would typically release very small slabs.  

Most of wind effect on slopes was from winds 2 days ago.  Today, however, winds were blowing up high out of the north east, visibly transporting snow in isolated areas across slope and over the ridgetops.  We did not travel on more NW-W to S facing slopes where this wind was occuring more dramatically.  We felt it was very likely that there would be isolated areas on steep convex slopes that very fresh windlsab sensitive to skier triggering would exist that could be hazardous.  

One full profile pit dug a few hundred feet below ridge in a shallow area near a rockband (see attached profile).  We chose this spot for it's shallowness (~1m), as snow depth increased quickly as we moved away from sides of slopes and rocks toward the middle, and we wanted to see how the basal facets were doing.  We did find well developed depth hoar, 3-4mm cup shapes with striations.  It was not very loose, however, at this relatively high elevation, and compression tests did not fail on it.  Relatively new windslab at the surface (~15cm thick) failed consistently and very easily in CT tests, sometimes upon isolation, and sometimes with simple shovel weighting, and failed and propagated during ECT test upon isolation.  High temperature gradiant in upper 50cm of snow pack will likely lead to faceting of the new snow that fell and was wind deposited last week.  

Coverage is generally good, snow at tree line and below was generally consistently soft and unconsolidated.  Higher up, very variable.   

Snowpit or crown profile photo or graph: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
More detailed information about the weather: 

Mostly sunny day with scattered clouds.  Calm winds at low to mid elevations, with moderate NE winds with occasional strong gusts above 10,000' which was visibly transporting snow in isolated areas.  

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