Kidney Couloir - Warming snow and coverage

KIdney Couloir
Submission Info
Sunday, January 17, 2021 - 11:45am
Red Flags: 
37° 54' 13.9788" N, 119° 12' 29.8692" W
Snowpit Observations
More detailed information about the snowpack: 

Spectacular day in the Mtns  ... if it's not snowing it might as well be like today :-)  Headed up to Kidney Couloir to see how things were softening on solar aspects with full sunshine and blue skies, barely any wind, and clear overnight skies which led to a good overnight refreeze.  All these factors led to just about perfect spring skiing conditions in this SE facing feature just before noon, and no worries of loose-wet instabilities.  The snow remained totally supportable to booting up with crampons toping out at 11:30am, with at most 10cm of boot penetration (closer to boot top in some spots on more south facing flanks).  

-11:15am, 12,000', south aspect: top 10cm was wet without much cohesion ontop of firm knife hard layer.  

-On the way down dug a quick pit at 10,900' on a SE (150°) aspect at noon: Total snowdepth (HS)=70-85cm, isothermal (0°C from top to the ground) and moist throughout.  The top ~6cm were melt-freeze grain conglomerates, grains measured 2.5-5cm (a.k.a. young corn).  The  Ski pen was ~1cm at this spot, and bootpen was ~3cm.      

-On the ski down the couloir around noon I heard rockfall coming down near one of the neighboring fingers.      

-On the exit from Kidney and Gibbs Lakes where the snow was shaded and not warmed by trees, it remained cold and wintery all the way down below 8000' at 1:45pm.    

In summary, higher elevation (>10,000') SE aspects didn't have enough time in the direct sun to become concerning for loose-wet instabilities, given today's clear skies, good overnight refreeze, and the short January day-length and low sun angle.  More directly south aspects could be another story later in the afternoon given a couple more hours of direct sunshine.       

*Able to drive to far side of lower horse-meadows, tire tracks stopped there (7,500') with about a foot of snow on the rd.  Enough snow to ski to and from car without walking, all-be-it a little adventure skiing on the way out navigating the bushes, rocks and logs, occasional bare spots and variable surface conditions (but not sticky! just a little sluggish at points where the snow was warmed by the sun and tree-heat radiation.) See photo for coverage in the trees ~8100'.   

Snowpack photos: 
Kidney Couloir
North facing chutes of Mt Gibbs above Kidney Lake
8100' snow coverage in the forest
Weather Observations
Blowing Snow: 
Air temperature: 
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 

Blue skies without a single cloud all day, calm winds except for only at the very ridgetop.

-7:45am @ 7,500' (lower horse meadows): Air temp= -4°C / 25°F.

-10:15am @ 10,200': Air temp = 0°C.

-11:30am @ 12,270' (top of kidney couloir): Air temp in the sunshine (shaded by ski) = +6°C/43°F, light west wind.

-12:30pm @ 10,100' below Kidney lake: Air temp in the shade = 2.5°C/37°F. 

-- placeholder --

ESAC receives significant financial support from ...