Snodgrass

CBAC 2014-15 Observations

NAME: Jeff, Donny

DATE: 20150222

ACTIVITY: Avy L2

LOCATION: Snodgrass
ELEV: 10,000
ASPECT: E/NE
WEATHER:  OVC, S1, Calm throughout the day, + < 0.5MM
AVALANCHE / SNOWPACK OBS:
No signs of instability until 13:30 w/ ~4.5″
13:00
SS-ASi- R1-D1-O  NE @ 9,700 slope Angle ~37*  very small moved only a couple feet before losing momentum
14:00
SS-ASi-R1-D1-O  NE @ 10,600 slope angle 40*  slow moving slough in forest @ ridgetop, no prop, stepping down into older facets 6-10″
SS-ASu-R1-D1-O    NE @ 10,200  slope angle 36*  30x45ft ran very slowly, 4.5″ of stormslab bonded to old snow, failing in old facets 6-10″ down & then gouging down entraining more facets like a slough
SS-ASi-R1-D1-O  @ 37* bordering alongside  same dimensions
SS-ASi-R1-D1-O     @ 37* (immediately next to previous) but running as a fan shaped loose dry.
Snowpack: large collapse with only 1 skier, immediately before these three small skier triggered on flats 80 feet away.  facets collpasing under a 2cm crust with storm slab stuck to crust.  Slight drop in elevation from ridge resulted in noticeably denser snow.  HS 100cm
on the 21st we obsereved a similiar collapse @ 10,000ft  (HS 100cm on 5 degree W slope) but with a group of 7 close together.  no cracks so weak layer could have been the facets failing under the 2cm breakable crust.  Or the still intact SH layer we found ~20cm down.
Bonding tests:
13:00 @ 10,200 ECTP2  SC  (15cm down in facets covered by 2cm crust & storm snow)
No signs of surface hoar layer being reactive in 3 different pit sites (8 seperate pits) in Snodgrass saddle zone between 10,200 -10,500ft.  Only faint traces of it remaining in 1 pit, otherwise unseen.
Dec 13 layer very visible to the eye & producing CTM to CTN results but no propagation.