Gothic obs from 2/12-2/14

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 02/14/2016
Name: Geoff Unger & Chris Pruden
Subject: Gothic obs from 2/12-2/14
Aspect: All aspects
Elevation: 9400-11000

Avalanches:
Weather: High pressure with lots of solar on Friday. Cloud cover moved in midday Saturday and it snowed lightly on Sunday. Light increased to Moderate winds as the little disturbance arrived on Sunday.
Snowpack: On Friday 2/12 we toured in the road and did beacon drills. Of note was how slight changes in aspect changed the character of the snow dramatically. All but the most sheltered terrain has developed a crust. Just touring up the road it is easy to see the widespread natural activity that happened as a result of the 2/2 Storm event with slabs running up to D2-D2.5 over the past 10 days

Saturday 2/13 We toured up Copper Creek to get snow profile information. We dug on a WEST aspect and had mixed column test results. Even on a relatively sheltered West the crest had formed to make skiing less than desirable. Link to snow profile below.

Sunday 2/14 We toured up to the Snodgrass-Gothic Saddle. There was still good snow available for skiing on NE, but as soon as we trended E even the slightest bit the dreaded crust appeared.

Compression Tests revealed Buried Surface Hoar down approx. 39 cm on hard results on a NE aspect
CT 26 SP down 37 V 2-3mm / .5-1mm
CT 16 SC down 39 V 2-3mm / .5-1mm
It is possible the first result was also a collapse, but had the appearance of a planar fracture where the second result was a clear drop of the column.

 

 

Gothic

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/15/2016
Name: Steve Banks
Subject: Gothic
Aspect: North, East, South
Elevation: 9400-12400

Avalanches:

Weather: Scattered morning skies with colder temps staying near or below freezing with light to moderate NW winds. Lots of plumes visible on the ridgetops especially midday.

Snowpack: Found good soft snow with 1-3″ of new blown in up to a foot deep at higher ridge top elevations. New snow not bonding well to old sun or wind crusts, but sticking to older dry snow. Still some lingering persistent slabs in some areas, but the snow is weakening and the slab is dissipating, especial ATL and BTL.
1 shallow windslab pocket produced a 10′ crack and 15′ downslope soft slab, but it was barely able to slide on firm wind pressed snow below. Hand shears on sunnier aspects show crust facet combos and no more moist or wet snow. 1 ECTP 11 SC in a fairly unrepresentative spot at the ridge line at 12,400 on a South facing slope failing on crust/facet combo.

Mt Emmons

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/15/2016
Name: Evan Ross
Subject: Mt Emmons
Aspect: North East, East, South East
Elevation: 9,000-12,000

Avalanches:
Weather: Mostly cloudy sky. Mostly light westerly winds at rigeline, with evidence of previously drifted snow.
Snowpack: New snow amounts in the 1-3″ range. Ski pen mostly about the same. No wind slabs found or an active persistent slab.

South east at 11,000ft in Coon glade had a 7cm VD (valentines day) crust with dry snow below. Same elevation on a more protected south facing slope in Coon Basin had a 15-30cm refrozen crust like thing with moist snow below, often to the ground.

East facing bowl ATL in Coon Basin has about 2-3″ new snow over wind effected snow surfaces.

Northeast facing NTL/BTL in Climax chutes was around 100cm HS with persistent slab structure but no obvious instabilities observed. Some 80% of that avalanche terrain, avalanched during the last natural cycle. Skier triggered one far running facet slough in an old bed surface, D1.

Touchy wind slabs

CB Avalanche Center2015-16 Observations

Location: Kebler Pass Area
Date of Observation: 02/15/2016
Name: Zach Guy
Subject: Touchy wind slabs
Aspect: South East, West
Elevation: 10,400-11,800 ft.

Avalanches: Skier triggered one fresh windslab up 18″ thick on a SE aspect above treeline (D1), and several very small pockets on west aspects near treelin (D1), running on storm interface.  SS-ASc-R1-D1-I
Weather: Overcast skies decreased to scattered by PM with direct solar. Moderate NW winds with light transport.
Snowpack: 9″ of new snow bonding poorly to the very stout crust buried yesterday. Drifting at upper elevations from NW winds. Green housing and PM solar caused low elevation, southerly aspects to moisten.

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Mt Emmons

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/13/2016
Name: Steve Banks
Subject: Mt Emmons
Aspect: North East, East, South East
Elevation: 9,200 to 12,300

Avalanches:
Weather: Sunny morning giving way to high clouds by noon. +2°C at 11 am near the top of Red Coon Glade. Increasing winds to strong by midday from the NW. Plumes and blowing snow off the peaks, but not much in the fetch to get transported.
Snowpack: Stout MF crust on SE slope softening by 10am. ATL most slopes are wind buffed and/or sun crusted. Red Lady Bowl left side (SW facing) had a 4″ suncrust with dry snow below. Wasn’t softening quite enough due to winds cooling the surface. NTL/BTL on North facing slopes still held dry snow and supportive pow. Anything rolling into the sun had a thin crust. Alpine slopes had stiff wind board from 4-8″ thick and 3-4 mm facets below. Shallower areas had all facets

Crested Butte Area

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/14/2016
Name: Steve Banks
Subject: Crested Butte Area
Aspect: North East
Elevation:

Avalanches:
Weather:
Snowpack: Skied NNE slopes up to 34* with no collapsing or whompingor recent avalanche activity. Mostly faceted and weak snowpack, though some persistent slab structure. Several hand shears revealed difficult to pull off, but somewhat clean shears between 40 and 60 cms below the surface. One on suspected surface hoar, the others on surface facets. HS around 100-130 cms. Steeper slopes are close to posing a facet sluff problem.
Temps remained cool, with noted temperatures of -4 to -2 C. Moderate morning winds calmed through the day and were varied by the terrain. Periods of S1 snowfall with little accumulation.

Below Treeline

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/14/2016
Name: Evan Ross
Subject: Below Treeline
Aspect: North East
Elevation: 9,000-9,500

Avalanches: Manny old D1-2 slabs form the last natural cycle in the area, on northeasterly slopes in the high 30 degrees or near 40 degree range.
Weather: Overcast sky, a few very light snow showers with only a trace of new snow at 1pm, NW winds were light down valley with stronger moderate gusts.
Snowpack: Quick couple hour tour. HS in the 90-110cm range. surface snow was a mix of wind board, but mostly faceted or decomposed surface snow. Ski pen in the 15-20cm range. Persistent slab structure is that but the slab the slab had broken down enough that it is no longer reactive.

Snowpack obs, Wash Gulch and Snodgrass

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/14/2016
Name: Zach Guy
Subject: Snowpack obs, Wash Gulch and Snodgrass
Aspect: North East, East, South East, South, South West
Elevation: 9,600 to 12,600

Avalanches:
Weather: S-1 snowfall. Moderate northwest winds and light snow transport. Overcast skies.
Snowpack:<1″ of new snow, fell on textured crusts on southerlies, windboard/wind rippled on upper elevation shaded aspects, and near surface facets below treeline on shaded aspects.  South and southwest facing aspects feel bomber right now, with refrozen wet grains deep into the snowpack; supportive to boot pen at all elevations.  SE aspects above treeline had semi-supportive crusts, 3″ thick or so.  Below treeline, the persistent slab structure on shaded aspects feels like it is faceting away and the weak layer/slab interface looks more homogenous than last week’s pits on similar aspects/HS.  Dug one pit on an ENE aspect of Snodgrass.   I got non-propagating results (ECTN, hard) on both the Jan 29 and Jan 14 facet layers, 40 and 60 cm deep approximately.   No signs of instability all day.  Some above treeline cornices are monstrous right now.

Gothic

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/13/2016
Name: EM
Subject: Gothic
Aspect: South East, South, South West
Elevation: 9300-12300

Avalanches: Two wet slides below treeline on either side of choke of spoon. Failed earlier in week. Snow in this area was wet to ground.
Weather: Warm temps with thin clouds. Consistent winds with strong gusting near and above treeline.
Snowpack: Below treeline on southerly aspects surface had crusts ranging from 5 to 12 cms. Below crusts, on most terrain over 20*, snowpack was wet to the ground.
Above treeline the snowpack had surface crust around 5 to 10 cms. Water had generally only made it 30 cms below surface. Snowpack was still mostly dry above treeline. In steep SE cross loaded start zone the HS was 180cms. Stability tests at this site produced no results, but there was clear large weak grains 30 cms thick at bottom. They were weak enough to be concerning. It would be difficult to impact this layer but would create a destructive slide. Terrain in same feature that was not loaded had HS of 100cms without concerning structure.

Wet snow obs

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/13/2016
Name: Zach Guy
Subject: Wet snow obs
Aspect: South East, South
Elevation: 9,200-12,400 ft

Avalanches:
Weather: Thin few to scattered clouds increased to thick overcast by late p.m. Strong to extreme gusts at ridgetop out of the NW, with light transport at times. Warm temps.
Snowpack: Strong winds were keeping surfaces mostly frozen at upper elevations, today. Above treeline on a 40* SE aspect, there was 2-3″ of refreezing melt-freeze crust, semi-supportive on skis, with dry snow below. On a 30* SE aspect below treeline, there was 3″ of very wet snow at the surface with moist snow down to the Jan 29th crust, about 15″ deep. On a 35* S aspect below treeline, the snowpack was entirely wet to very wet, about 20-24″ total depth. No signs of instability today.