AVALANCHE/SNOWPACK OBS: Many sluffs spindrift off steep terrain & cliffs, slashed a couple 35-40* small roll overs & only got one tiny slab to pop off, the rest sluff’d

SNOWPACK: Numerous (>12) collapses & shooting cracks on flats & N-NE slopes up to 30* 9,500ft to 12K failing ~30-40cm into the old NSF with the underside of the slab (can hold it in your hand) from last week embedded with facets. Ski pen 30-40cm

DATE: 20150227
LOCATION: Emmons
ELEV: 9,000-12,400′
ASPECT: SSE
WEATHER: OVC & BKN, snowing S1, light NW winds at ridge top in alpine as of 1200

AVALANCHE/SNOWPACK OBS: About 25-30cms of dense, thick storm / wind deposited snow in the alpine as of 1200. Small cracking at ridge top but no propagation. Small and thin eggshell rime crust observed above TL on low angle SSW slopes. 2 small D1 slides ran in steep E terrain below ridge top and from exposed rocks and cliff bands in past few days.

AVALANCHES:

WEATHER: Mostly cloudy with periods of S-1 and S1. Calm

SNOWPACK: Hand test: top layer had 5cm of recent snow (last 48 hours), overlying a sun crust. Below the sun crust were 5 cm of faceted grains, overlying a melt/freeze crust. Hand and pole couldn’t penetrate this melt/freeze crust.

UPLOADS:

AVALANCHES: Widespread, touchy persistent slabs on N/NE aspects BTL. Almost every rollover steeper than 35 degrees we approached today either triggered remotely or with a ski cut., about 10 slides in total. Slabs ranged from 10″ to 18″ thick, 10 to 100 feet wide, and ran up to 500 vertical feet. Failed on near surface facets. that were buried at the beginning of this late-Feb storm cycle. Most were D1, a couple D1.5’s with debris up to 5 feet. Two were remotely triggered from flat terrain. SS-AS-R1-D1/1.5-O

WEATHER: Overcast. S1 midday increased to S3 by late afternoon. Light easing to calm winds.

SNOWPACK: N/NE aspects: 12-18″ of F+ recent snow, no wind affect, over the Feb 16th facet layer (F hard), which is rotten to the ground. Very reactive interface. Widespread cracking, collapsing, and skier triggered slides.

S aspects. 4-6″ of new snow over the most recent Meltfreeze crust (Feb 24 crust), which is 2″ thick and supportive. About 2″ of mixed forms below that crust to the February 20th crust, which is knife hard to the ground. No signs of instability or sluffing on steep terrain.

UPLOADS:

AVALANCHES: 4 different slides visible from basin floor. All from recent wind loading

WEATHER: Snowy with mild winds in the tress, large gusts on ridgelines and peak visible from basin floor

SNOWPACK: Solid with no instability below treeline. Once into the tongue below M-Face…experience numerous collapses but nothing broke loose,. Turned around and skied trees

UPLOADS:

AVALANCHES:

WEATHER: temps low 20’s, cloudy obscuring any chance at valley wide obs, snowing off and on, random squalls but no consistent winds where we were

SNOWPACK: six inches new overnight, ski pen 16 inches. some sluffing on steeper pitches but only new snow moving and pitches not long enough for sluffs to sustain or entrain so I remain to slay pow again. Crusts under new snow on anything with east tilt.

UPLOADS:

AVALANCHES: NW winds loaded Bender (E-facing 38º) just below the ridge and we triggered a slide that was similar to the other two slides there this season. Elsewhere, wind-loading seemed insignificant and unreactive though we didn’t go through any of the chutes. We cleaned off the cornice above Candy’s (E-facing 38º) with no results. The apron below Candy’s / Bender was very grabby skiing on the breakable crust.

WEATHER: 19” in the last 7 days.

SNOWPACK: 2-5cm MFcr throughout most aspects/elevations with the exception of Upper WW where the Feb 24 crust was only 1cm. Sunset right had no MFcr. 5” low density snow skied well today, especially wests and shady. Ski quality is slowly improving on majority of terrain.

UPLOADS:

AVALANCHES: None new observed in the area of our tour.

WEATHER: Clear skies and calm winds in the morning. Clouds (overcast) and wind (light) building from the west by mid day and flurries (s1) by 2:00pm. Temperatures in the upper teens up to mid twenties.

SNOWPACK: New snow from yesterday/ last night totaling 5cm sitting on a sun/ temperature crust from Tuesday? Crust layer more noticeable as the aspect turns more east. 30 cm from the weekend storm. Boot pen: 44cm/ Ski pen: 14cm. HS: 200cm at northeast facing pit site at 10550ft. Results as follows, CT16/ ECTP14 at weekend snow/ old snow interface 35cm down (on 1-1.5mm facets)+ PST33/100End down 35cm on 2015-02-21 all @ 32 degrees.

UPLOADS:

AVALANCHES:

WEATHER: WEATHER: Mostly Cloudy with several snowfall bursts throughout the day. About 1″ new near the top of Coney’s at 2pm. Light to moderate winds where down valley at BTL elevations and westerly at ridgeline.

SNOWPACK: SNOWPACK/AVALANCHE OBS:
Only significant result was an intentionally skier triggered windslab at the top of the bowl. Propagated 40ish feet wide with an average crown of about 4″. Ran 150 feet and was a D1. Windslab failed on lower density storm snow.

Everywhere else we traveled in the bowl we didn’t really find any form of a slab within last weekends storm snow. There were certainly areas to be avoided at all elevations where you likely could have triggered a similarly small windslab.

Dug a pit at 10,700ft. HS 140. Last weekends storm snow was 35cm on a 2cm MFcr. Below this crust was F hard facets that where progressively harder all the way to the ground where they had become 1F hard. The facets just below the MFcr was the layer of concern but needed more of a slab on top to propagate a result. CTH SC, ECTN 20 on this interface.

Shady slopes below treeline have the most concerning structure as the storm snow is sitting on F hard weak facets to the ground. Though we didn’t come across a slope where last weekends storm snow had formed a slab, yet. Unless recent winds had cross loaded the slope. Near the trailhead there had been several storm slabs that failed naturally and where all D1 in size. These storm slabs where shallow and appeared to fail within the storm snow and not on the old snow interface.

UPLOADS:

IMG_0213

AVALANCHES: Skier triggered storm slab. Broke 1 foot deep propagated 100 feet on steep, shady alpine terrain and ran 1000 feet

WEATHER: clear calm

SNOWPACK: 10-14 inches of new snow, now wind.

UPLOADS:

avy