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.

 

 

Cracking/collapsing on Whetstone

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 02/07/2016
Name: Zach Guy
Subject: Cracking/collapsing on Whetstone
Aspect: North East
Elevation: 10,000-11,000 ft

Avalanches: Most obvious paths ran naturally in this terrain on 2/1. D1.5 to D2’s in size. Took a quick look at one crown; ~2 ft thick over F+ 2-3mm facets. These paths also ran in December. Unfortunately, the bedsurfaces are crusty and there is 3-6″ inches of faceting snow above them already, ripe for 3x repeat offender if we get another big storm.
Weather: Light winds below treeline. Continued snow transport observed over Anthracite Range and West Elk Range, but minimal transport looking towards Pearl Pass, Brush, Cement, etc. Few clouds.
Snowpack: See video. On shaded low angle terrain below treeline, the snowpack was 50cm of slab (F to 4F+) over 50 cm of facets (Jan 14 interface, F+, 1-2mm). We crossed about 10 open meadows, and got 2 rumbling collapses. One as we regrouped and were stepping out of skis, the other by jumping on the snowpack on skis. The Jan 29th surface hoar layer (2-4mm, F) is also preserved about 30-35 cm deep, and propagated in 2 out of 3 of our extended column tests. (ECTPM, SC, Q1). We got several shooting cracks up to 20 feet long on this layer on small rollovers.

IMG_5748-002
IMG_5746-002
Profile NE aspect BTL

Profile NE aspect BTL

CBAC Snodgrass Study Plot Snowpit

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 01/30/2016
Name: Jimmy Buchanan
Subject: CBAC Snodgrass Study Plot Snowpit
Aspect: North East
Elevation: 9,800′

Avalanches: None
Weather: Overcast, intermittent periods of light precip.
Snowpack: See profile

Snodgrass-Jan.-30

Coney’s

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 01/23/2016
Name: Dave Bumgarner
Subject: Obs at Coney’s
Aspect: North
Elevation: 10800

Avalanches: Saw some small D1 avalanches on Schuylkill in the Chiquita Bowl Area from the store slab.
Weather: Overall pleasant day, sunny, no wind just at the freezing point.
Snowpack: No signs of instability during my tour Dug a pull Profile near the ridge in 1st bowl (attached). Saw some moderate CT results at a layer at 70 cm.

Coneys-First-Bowl-Pit

CBAC Snodgrass Study Plot Snowpit

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 01/19/2016
Name: Jimmy Buchanan
Subject: CBAC Snodgrass Study Plot Snowpit
Aspect: North East
Elevation: 9,800′

Avalanches: None.
Weather: See profile.
Snowpack: See profile.

Snodgrass-Jan.-19

Avalanches at Kebler Pass & Irwin

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Kebler Pass Area
Date of Observation: 01/17/2016
Name: Zach Guy
Subject: Avalanches at Kebler Pass & Irwin
Aspect: West, Southeast
Elevation: N/BTL

Avalanches: On a SE aspect near treeline, a 2lb handshot triggered a large soft slab, 65 cm deep and ~200 ft wide, that failed in a thin facet layer below the Jan 14th meltfreeze crust.  SS-AE-R2-D2-O.  See profile. Widespread storm slab instability with more than a dozen natural and skier/snow cat triggered soft slabs (Fist hard, 3-10” deep, failing on precip particles) along various aspects of Kebler Pass Road and on Irwin terrain. Minor propagation decreased through the day (max 60 feet wide, avg 20-30 ft), and easily managed, ran more like loose snow avalanches. Harmless in size. SS-ASc/AK/N-R1-D1-S
Weather: Calm to light winds, with moderate gusts from S to W. S-1 to S2 snowfall. Overcast skies.
Snowpack: 18” of very low density snow with minimal wind affect fell last night. On west aspects N/BTL, the storm interface (Jan 14th near-surface facet layer) is ~30” deep in relatively windsheltered terrain; deeper or shallower in wind affected terrain. One pit in an untrafficked area showed the layer is unreactive; size/hardness change was indistinct, with small grained rounding facets at the interface. See profile 1. On SE aspects near treeline, the slab was 26″ deep, but denser from wind effects, over reactive crust/facet/crust sandwiches. See profile 2 and avalanche ob.

Upper snowpack on a west aspect near treeline
1/17. Crown Profle SS-AE-R2-D2-O

1/17. Crown Profle SS-AE-R2-D2-O

1/17. Explosive triggered slab avalanche at Irwin. SE aspect NTL.

1/17. Explosive triggered slab avalanche at Irwin. SE aspect NTL.

1/17. Explosive triggered slab avalanche at Irwin. SE aspect NTL.

1/17. Explosive triggered slab avalanche at Irwin. SE aspect NTL.

1/17. Explosive triggered slab avalanche at Irwin. SE aspect NTL.

1/17. Explosive triggered slab avalanche at Irwin. SE aspect NTL.

CBAC Snodgrass Study Plot Snowpit

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 12/31/2015
Name: Jimmy Buchanan and Zach Guy
Subject: CBAC Snodgrass Study Plot Snowpit
Aspect: North East
Elevation: 9,800′

Avalanches: None.
Weather: See profile.
Snowpack: See profile. Observed a very loud and widespread collapse while skinning to the study plot.

December-31st-Snodgrass

Park Cone (Taylor Park Area)

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Cement Creek Area
Date of Observation: 12/28/2015
Name: Ian Havlick
Subject: Park Cone (Taylor Park Area)
Aspect: North, North East
Elevation: 9200-10500

Avalanches: Hard to see, but did observe a few large debris piles on S-SE facing slopes of the Collegiates/Sawatch, as well as a large slide partially blown back in on Matchless Mountain, and a 50ft wide slab triggered by snowplow below road to lake ice below.
Weather: Increasing clouds in afternoon. Cold temperatures, ~15ºF. Calm.
Snowpack: Average HS 75-90cm. 6mm surface hoar on every opening in trees. Large, stiffening storm snow (F>1F hardness) mixed with 1 to 3 layers of surface hoar in bottom 30-50cm (before most recent storms), and 3-4mm cupped depth hoar at the ground. Two ECTs produced ECTP24 and ECTP27 both failing 30cm from ground at hardness and grain type/size difference. 24º slope, NNE aspect @ 10,200ft. At ridgetop of surrounding peaks, hardly any snow on W-NW facing slopes.

20151228ParkConeGraphicalPit-1

3-4mm depth hoar20151228ParkConeNSFSH
4-6mm surface hoar and near surface facets
20151228ParkConePit2
observation wall from same pit without labels

 

Mt Emmons / Red Lady Glades

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 12/27/2015
Name: Seth Beers
Subject: Mt Emmons / Red Lady Glades
Aspect: South East, South
Elevation: 9300 – 11300

Avalanches: No new avalanche activity observed beyond the carnage from the past several days. Toured quite a bit outside of the main skin track and didn’t observe any cracking or collapses in open areas.
Weather: Clear w/ strong temperature inversion. -2F at TH and ~25 at 11K @ 1pm. Calm.
Snowpack: Large settlement has occurred on S & SE aspect since Xmas storm (see pic). ~20 – 40cm based on aspect and elevation. Storm slab has consolidated (now 4F to 1F) and seemed to increase in strength as the temps and solar continue to influence the snow during my tour. Surface snow was even gaining a bit of moisture during my descent below ~10500 at select aspects. Ski pen of 10 – 20 cm, Boot pen of ~60 cm.

Slab sits above crusts, depth hoar, or directly on the ground based on aspect and elevation. Where it is not resting on the ground the interface is scary. Compression test produced Q1 sudden collapses (CT3 & CT13) at depth hoar layer. The column would also produce a sudden planar fracture above the melt freeze crust as it collapsed in the pit.

General feeling was the slab is gaining strength and finding a very delicate balance with underlying weak layers but the potential is growing.

20151227RLGladesBeersSettlementCones
12.17.15-Profile