Avalanches:
Weather: Warm day today with solar, high of 34F.
Snowpack: 2-Chutes: One small collapse in the upper pitch, Good cracking on upper 5lb hand shot (50 cm to ground). 9lb Airblasts in Middle of 2-chutes and in Widow
maker with no results. JB Jungle/Mean: 9£ cover shot in JB trees produced SS-AE-R1-D1-G. Slide
strained through trees and petered out on JB apron. 9£ hand shot in JB/Mean
interface left surface cracking, but skiing next to crater produced a medium collapse
post detonation. 9£ Airblast in JB apron below trees no results.

A slope in between double handshots in Mean, produced 20 ft shooting cracks
(depth unknown), no collapsing noted. 9£ Airblast in Mean produced no results.
Outer Limits: No signs of instability with ski cuts and big airblasts. Profile below
rock band: HS 150 w/ 40 cm’s of 2mm Facets. ECTX. CTM24 SC @ 40cm 2mm
Facets. Three 5lb. Hand shots simo in Round Two below OL w/ no results.

• profile-1.pdf

Avalanches: None.
Weather: See profile. Scattered clouds, calm wind, no precipitation.
Snowpack: See profile. Cracks and whumphing observed on very low angle terrain during skin to study plot. Slab from recent new snow was very reactive on the old, preserved layer of depth hoar.

IMG_2718

12/23 Snodgrass Study Plot

Avalanches:

Weather:

Snowpack: See profile

Avalanches: See crown profile. Investigated the crown of a unintentional skier triggered slide that occurred earlier in the day. Skier was initially caught but not carried. SS-ASu-R1-D1-O. The avalanche broke on a layer of fist hard facets below 12/11 melt freeze crust. It was on a slightly cross loaded feature, with crown height ranging from 35cm to 20 cm. Approximately 75 feet wide and 200 vertical feet.

Weather: Light snow transport from light to moderate NW winds. Scattered to broken skies. Mild temps.

Snowpack: See profile.

image2

20151218-thortons-crown-profile

Weather: See profile. No precip yet.
Snowpack: See profile. No signs of instability.

profile-2

Avalanches: We triggered cracking and a very small windslab avalanche, 4″ deep x 15 feet wide, on several windloaded rollovers facing SE. Also some small cracks where the persistent slab structure was shallow (<20 cm) but stiff from wind.
Weather: Scattered, thin clouds. Moderate to strong westerly winds with light snow transport at ridgetop. Mild temps, no precip.
Snowpack: In summary, widespread weak and faceted snowpack on all aspects, with decaying and unreactive persistent slabs except in isolated, heavily windloaded features. See video
Below treeline: Snowdepth is less than 30 cm, entirely faceted, fist hardness on all but southerly aspects. Ski pen to the ground. Most southeast through southwest aspects are bare, or hold shallow stacks of melt-freeze crusts with varying degrees of faceting between crusts.
Near treeline on N to E aspects: Snowdepth ranged from 40 to 80cm, with fist hard facets in the lower half, and in windloaded areas, faceting slabs in the upper half (4F hardness). No results in snow pits. Ski pen was trap-door, nearly to the ground.
Above treeline on N to NW aspects: Predominately thin snowpack due to wind erosion, <60 cm, and faceting throughout, with ski pen near the ground.  Isolated and discontinuous pockets of supportive snow with 1F to 4F faceting slabs over softer facets, similar to near treeline, but stiffer and thicker in the more heavily windloaded features.  In one crossloaded gulley, the snowpack was 100 cm deep and showed propagating test results on depth hoar near the ground.  On SE aspects ATL, we found thick, supportive crusts on steep (~40*) slopes, and an entirely faceted snowpack with thin, breakable midpack crusts as the slope angle lowered to mid 30’s. No slabs on this slope.

Above treeline, North aspect on Mt. Emmons

Near treeline, NE aspect on Mt. Emmons.

Weather: Few clouds, calm wind.
Snowpack: Continuous snow coverage now on all aspects/elevations except for some below treeline southerly slopes. Snow surface was re-freezing crusts on every slope SE, S, and SW. Widespread surface hoar layer at all elevations on shady aspects, ranging from 2-3mm at lower elevations to 1mm at higher elevations. Some minor faceting below the surface hoar as well. Last week’s snow is now denser and supportive, ranging from 20cm or less at 10,000 feet and up to 60 cm at 11,500 ft. Encountered old facet layer below last week’s snow around 11,000 feet and higher on northerly aspects. Snow profile here showed 45 cm of slab over 10 cm of 1mm facets. Propagating results in stability tests and got a moderate collapse about 10 feet from my pit as I was leaving. See attached profile. Slabs become more variable in depth and density at higher elevations due to wind effects. Observed some minor cracking above 11,000 feet as well.