Remote avalanche in Oh-Be-Joyful

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 12/04/2016
Name: Zach Guy and Evan Ross
Subject: Remote avalanche in Oh-Be-Joyful
Aspect: North East, East, South East, North West
Elevation: 10,800 to 12,600 ft

Avalanches: See photos. Evidence of widespread natural avalanche cycle in Peeler and Oh-Be-Joyful Basin from 11/27-11/28 storm, on northerly aspects N/ATL, small to large in size.. Faint crownlines and debris on Scarp Ridge, Purple Peak, and a lot of north facing terrain that we got views of. ~15 x SS-N-R1/2-D1/2-O/G
On a NW aspect ATL, we remotely triggered a persistent slab that failed at the ground on 3mm depth hoar. The crown was 2-3 ft deep, up to 1F hard, ~300 ft wide. Triggered from ~800 feet away on low angle, NE facing terrain. SS-ASr-R1-D2-O/G
We also skier triggered one small windslab on a crossloaded NW aspect ATL, less than a foot thick. SS-AS-R1-D1-U.
Multiple small sluffs observed on various aspects from the recent snowfall, all harmless.
Weather: Clear skies increased to scattered clouds. Light to moderate westerly winds with occasional light snow transport. from ridgetops.
Snowpack: On E and SE aspects ATL: One test pit and numerous hand pits showed a ~60-80 cm slab (typically 4F) over .5-1 mm rounding facets, typically 4F- or F+. Two ECT’S showed non propagating results (ECTN H Brk and ECTN M PC). We traveled on several slopes up to 45 degrees with no signs of instability. There is a new meltfreeze , ~1cm thick, forming on the surface of S to SE aspects, with small faceting below.
On NW to N aspects N/ATL: We experienced 4 booming collapses, with shooting cracks radiating up to 1,000 feet away. Quite alarming! Structure consisted of 50 cm to 80 cm 4F to 1F slabs over 4F small grained facets over 3mm fist hard depth hoar. It appears that more than half of avalanche terrain had flushed naturally during 11/27-11/28 storm, so the snowpack structure will be quite variable from slope to slope now. Snow surfaces consist of DF grains, windpacked grains, and small facets (less than .5mm)
Some minor, shallow cracking on all aspects ATL isolated to ridgeline windloaded locations.

Remote triggered slide today. NW aspect ATL

Remote triggered slide today. NW aspect ATL

Profile dug near the avalanche trigger location.

Profile dug near the avalanche trigger location.

Shooting cracks up to 1000 feet away from trigger location.

Shooting cracks up to 1000 feet away from trigger location.

NW aspect ATL

NW aspect ATL

Shooting cracks from trigger location.

Shooting cracks from trigger location.

NW aspect NTL

NW aspect NTL

Old crown. N aspect ATL

Old crown. N aspect ATL

Old crown. N aspect NTL

Old crown. N aspect NTL

Old crown. NW aspect NTL

Old crown. NW aspect NTL

Old crown. N aspect NTL

Old crown. N aspect NTL

Old crown. NW aspect NTL

Old crown. NW aspect NTL

NW aspect NTL

NW aspect NTL

Old crown. ENE aspect Scarp Ridge

Old crown. ENE aspect Scarp Ridge

E aspect ATL

E aspect ATL

Old crown. NE aspect, Scarp Ridge

Old crown. NE aspect, Scarp Ridge

Alpine observations

CB Avalanche Center2016-17 Observations

Location: Paradise Divide Area
Date of Observation: 12/02/2016
Name: Evan Ross/Ian Havlic
Subject: Alpine observations
Aspect: North, East, South, West
Elevation: 11,200

Avalanches:
Weather: Obscured and overcast sky. Snowfall rates were mostly in the S-1 to S1 range, but rates picked up for an hour here and there to around S2. Calm winds with no new drifting snow observed.
Snowpack: In general, the Thanksgiving Storm and following large storm around 11/26 were creating a nice looking homogeneous snowpack. Any layers of concern or potential layers of concern were near the ground, having formed during the shallow or non-existent snowpack before Thanksgiving. No obvious signs to instability while traveling through east to south to southwest facing slopes. Ski Pen around 25cm.

Dipped into the top of one north facing slope at 11,200ft. Nothing new, HS 130, progressively harder snowpack with depth (F to 4F+) over about 18cm of dry, large facets. The ground cover at the base of the snow pit wasn’t perfectly planner and had some variation in depth due to rock outcrops. Though thats probably representative of the ground cover across the terrain. ECTP 22 SC, ECTN.

East facing 34 degree slope at 11,200ft. HS 140. Same structure as above with the basal facet layer at about 10cm thick, 4F- hard, and both smaller and moist then on the north facing observation.

Cascade/Baxter Basin

CB Avalanche Center2016-17 Observations

Location: Paradise Divide Area
Date of Observation: 12/02/2016
Name: ian havlick
Subject: Cascade/Baxter Basin
Aspect: North, North East, East, South East, South, South West, West, North West
Elevation: 10,000-11,600

Avalanches: no avalanches or signs of instability observed except for very minor new snow sloughing in extreme terrain.
Weather: Orographic snow all day, heavy at times. 10-20cm new snow. very light northwids at ridgetop, otherwise calm winds
Snowpack: Very impressive, generally good structured snowpack on all aspects but northerly. Many pits on NE, N, NW, E, and S facing slopes ATL. Generally 120-160cm snowpack with fist to 1 finger hardness snow descending until last 10cm near ground on northerly slopes. Last 10cm consisted of 3mm striated depth hoar. Specifically looked and stomped on steep, northerly terrain with no signs of instability, and good structured snowpack. One profile dug on S-facing slope at 11,500ft, had one mid-pack concerning crust, almost a greenhouse crust, with some very small associated facets.

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Mineral Point

CB Avalanche Center2016-17 Observations

Location: Paradise Divide Area
Date of Observation: 12/03/2016
Name: Zach Guy
Subject: Mineral Point
Aspect: East
Elevation: Above treeline

Avalanches: See photo. Two small, D1 to D1.5 slides on E face of Mineral Point. One crown visible.
Weather:
Snowpack:

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Collapsing snowpack

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 12/02/2016
Name: Than Acuff
Subject:
Aspect: North, North East
Elevation: ATL, BTL

Avalanches: None seen
Weather: low 20’s, light snow off and on, slight breeze out of southwest, zero snow transport
Snowpack: 2-3 feet deep, ski pen 12 inches, boot pen to the knees. Collapsing at the top of steep roll overs (35-40 degrees), big enough to shake snow off trees, large cracks but nothing moved. Collapsing in flats as well

Red Lady crown investigation

CB Avalanche Center2016-17 Observations

Location: Crested Butte Area
Date of Observation: 12/02/2016
Name: Zach Guy and Ben Pritchett
Subject: Red Lady crown investigation
Aspect: South East
Elevation: Above treeline

Avalanches: Investigated 2 crowns of recent remotely triggered avalanches. See photos. Extended column tests produced hard to additional loading propagating results on 1mm facets near the ground, with spotty crust distribution above the weak layers.  Slabs ranged from 40 cm to 100 cm 4F to P hardness, depending on wind effect.
Weather: Overcast skies. Light SE winds. Light snowfall.
Snowpack: Snow depths increased from 25-30 cm below treeline, up to 130 cm in the heaviest wind drifted features above treeline. Near and below treeline, the snow was generally too incohesive and shallow for avalanche concerns; the potential exception would be heavily windloaded features. The base of the snowpack is comprised of 1mm facets, and there was some very small and localized collapsing on this layer near treeline. Above treeline, this same basal weak layer exists, with more of a cohesive slab above, ranging from ~40 cm to ~100 cm

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Purp Skurp

CB Avalanche Center2016-17 Observations

Location: Paradise Divide Area
Date of Observation: 12/01/2016
Name: Dustin Eldridge
Subject: Purp Skurp
Aspect: North, North East, East
Elevation: 9500-11500

Avalanches: Saw a few old, blown-in crowns out in the distance of Baxter Basin and the north face of Cascade.
Weather: Day started relatively warm (10-15f) and continued to warm as the day went on. Partly cloudy skies began to creep in before the noon hour and by 1-2 skies became more overcast. Wind picked up a little bit in the afternoon but snow transport was very minimal. Definitely had a few instances of getting ‘greenhoused’, and saw some roller balls. Otherwise, sun’s impact on snow was limited.
Snowpack: Snowpack seems to be settling well. Ski pen is around 15-20 cm. Pack grew from 60-70 cm on E and NE slopes towards the valley floor to around 110-120 cm getting closer to treeline. Mostly right-side up, with a small crust-facet combo found in the basement of our NE facing pit at around 11,200 feet. CT21 and CT24, both Q1 shears at around 75 cm from the bottom. Weak layer was hard to identify from the pit wall, I imagine it was either a small layer of near-surface facets or surface hoar; did not notice much of a density change at the weak layer. Otherwise, no signs of instability noted.

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Schuylkill Peak avalanche and snowpack obs

CB Avalanche Center2016-17 Observations

Location: Paradise Divide Area
Date of Observation: 11/30/2016
Name: Zach Guy
Subject: Schuylkill Peak avalanche and snowpack obs
Aspect: North East, East
Elevation: 9,500 – 11,700 ft

Avalanches: Multiple crown lines across the N/NE/E bowl of Schuylkill Peak, faintly visible because they ran naturally mid storm. Hard to tell whether they originally connected or were separate slides. Debris was completely smoothed over by snow and wind. I would estimate they were D2 in size, failing on old snow layers near the ground. Vis of surrounding terrain was obscured by clouds, so no other avy obs.
Weather: Calm winds in basin. Light snow transport observed at peak summit. Cold temps. Scattered to broken skies.
Snowpack: On E to NE aspects.: Snow depth increased from 75 cm below treeline to 115 cm above treeline, with settled recent storm totals ~60 cm below treeline, and variable above treeline due to wind drifting.
Below treeline, the snowpack was generally right side up, with moist 1mm rounding facets at the ground and a soft 60 cm slab above. The base of the snowpack began to feel increasingly hollow with elevation gain, but no sharp hardness changes. Hand pits showed dry 1mm facets near the ground below a 60-70cm soft slab. No cracking or collapsing observed on numerous small, steep rollovers near and below treeline. The bowl above treeline appeared to have mostly avalanched naturally, leaving a snowpack of ~20 cm of post-release fist hard snow over grass/talus

NE Aspect BTL

NE Aspect BTL

Crownline on ENE face of Schuylkill Peak

Crownline on ENE face of Schuylkill Peak

Zoom in of crown, ENE aspect

Zoom in of crown, ENE aspect

Faint crown lines, N aspect of Schuylkill Peak

Faint crown lines, N aspect of Schuylkill Peak

Crown line profile, ENE aspect ATL

Crown line profile, ENE aspect ATL