Observations

Date of Observation: 02/22/2021
Name: Zach Kinler Eric Murrow

 

Zone: Northwest Mountains
Location: Westerly descent from Elkton Knob down towards Pittsburg
Aspect: South West, West
Elevation: 9,000′ – 11,200′

 

Avalanches: One unobserved avalanche off Elkton Knob in a very drifted southwest feature at 11,000′. A relatively small feature but the avalanche failed at the ground with a crown over 4 feet. Hardslab blocks ran further than I would have expected on this feature knocking down a 12′ tree with a 3″ trunk. Given snow refill on top of some tall blocks, I estimate this ran around 13th or 14th. Skiing through the debris blocks would be a challenging and dangerous task.
Weather: Clear skies, with light winds, and mild temperatures. Sunny slopes at 11K were moist by the early afternoon. The only observed snow transport was on Purple Ridge with winds blowing up a north-facing alpine slope drifting onto southerly slopes.
Snowpack: Dug a profile in below treeline west-facing terrain for GMT descent route (see photo). No propagating test results in ECT even when hammering on the column after standard test but PST failed prior to 50% of cut length. These slopes have around 130-150cm snow depth with slabs around a meter thick caping weak layers from early in the season. No signs of instability underfoot, but we moved thoughtfully through the terrain given the dangerous potential size of avalanches. Sunny slopes were moist by the afternoon below and near treeline, and shaded slopes have lightly faceted surfaces which made for fast and fun skiing.

 

 

Photos:

 

Date of Observation: 02/21/2021
Name: Irwin Guides

 

Zone: Northwest Mountains
Location: Irwin
Aspect: West
Elevation: NTL

 

Avalanches: Field of screams. Single hand shot in a slight gully feature that had been loaded from SW winds left a fractured slope. Fracture ran approx. 100′ and was open to the ground. Tested the slope
after w/ a 10# AB resulting in a size 2 HS braking several medium sized trees and running full track. Field of Screams HS-AB-R2-D2-O (50cm x 30m x 350m). The slab was isolated to that feature Remotely triggered wind slab Castle Valley.

Photos:

Date of Observation: 02/20/2021
Name: Marcel Medved

 

Zone: Northwest Mountains
Location: Washington Gulch near Elkton
Aspect: South, West
Elevation: 10,400-10,600

 

Avalanches: Wind loaded, fresh slides on Friday? West Side of Gothic Mtn. Photo does not show very well.
South Side of hill above Mosquito Hut.  CBAC Note:  These slides were first observed 2/14.
Weather: Saturday 9:30am, sunny, calm 20F
Snowpack:

 

Photos:

Date of Observation: 02/20/2021
Name: Marcel Medved

 

Zone: Northwest Mountains
Location: Anthracite Mesa at Elkton
Aspect: East
Elevation: 11,000′

 

Avalanches: 2 fresh avalanches (Friday?), entire hill sides and 1 smaller older slide  CBAC Note:  These slides were first reported 2/14.
Weather: Saturday morning 9:30am Sunny, 20F, calm
Snowpack:

 

Photos:

Date of Observation: 02/21/2021

Zone: Northwest Mountains
Location: Axtell skin track & kebler road
Aspect: North, South
Elevation: N 10,400 & S 9,500

Avalanches: none
Snowpack: We skied axtell skin track today…. avy course;chose site to demonstrate the difference between tree bomb influence of PWL’s in snowpack BTL and “open glades” where there is little effect from the canopy.

Pit #1: @10,400 due N @ 360* in a 20mx20m opening in the tight mature forest:
2 x ECTP (22 & 28) SC (informal, cleared off the top 25cm of F fluff b/c HS is 145cm) failed 25cm above the ground/120cm down on 4-5mm FC.
Slab is 4F & 1F+

Pit #2 5m away from pit #1: ECTX (presumably heavily influenced by the canopy & tree bombed out, as HS was 95cm and ~1.5m from 3 mature spruce arranged in a triangle

Pit # 3 Just off Kebler road at the Axtell weather station/sled park S 162* ECTP (28) SC 25cm up from ground on 4-5mm FC in (CO shit sandwich of MFCR & FC layers) HS 80cm

 

Date of Observation: 02/20/2021
Name: Emilio Alcala

 

Zone: Northwest Mountains
Location: Axtell Skin Track Glades
Aspect: North
Elevation: 10,050

 

Avalanches:
Weather: Mostly Sunny, West winds building, Warm-Hot in the sun, Cold in the shade.
Snowpack: 2 dig sites, 20 ft apart. Site 1 open relatively open glades, Site 2 tuckered in near tighter trees.
Site 1 HS 140cm, ECTP H
Site 2 HS 90cm, ECT N
Visually different basal layers, tree bomb compression/distrubance? (peppered as shown in photo from nearby, +/- 100m from dig)

 

Photos:

Date of Observation: 02/19/2021
Name: Ian Havlick

 

Zone: Northwest Mountains
Location: Scarp ridge/Indy Basin/Elk Basin/Mount Emmons
Aspect: East, South East, South, South West, West
Elevation: 9,000-12,400

 

Avalanches: SS-N-R2-D2-O. Natural Persistent slab avalanche failing within last 24hrs on SE facing, heavily windloaded slope aet 12,000ft. Looked to have failed initally from cornice or additional windloading on 2/3 layer then quickly stepping down to rock on steep faceted slope. Debris ran far and entrained surprising amount of debris.
Weather: Cold. Blustery WNW winds 10-20 G40. Overcast. no new snow accumulation, minimal solar radiation.
Snowpack: Below and near treeline slopes ranged from 120-150cm+ in terrain traveled. Above treeline snowpack was variable as expected and scoured near ridgetop as per usual. Interesting reverse loading occurring with eroded cornices and deeper than expected sections of Scarp, especially above Evans Basin near the Gunsight Road. Pole probing continues to reveal poor structure with weak facets near the ground, although closer to 2-3mm facets in terrain I poked at. We traveled conservatively and assessed recent wind loading in terrain traveled and well as guarded against larger and wider slides given the structure

 

Photos:

Date of Observation: 02/20/2021
Name: Andrew Breibart

Zone: Northwest Mountains
Location: Mt Emmons
Aspect: East, South East
Elevation: ATL, BTL, NTL

 

Avalanches: Photo from south ridge of Mt. Emmons facing west towards Kebler pass. This modified photo shows an avalanche in Beckwith Range which may have been captured in the blitzkrieg of avalanche observations the past 2 weeks. Looks like D1/1.5 from afar.
Weather: Excellent visibility today with some cloud cover
BTL: light winds and hot. no jacket or gloves.
NTL/ATL: moderate winds with gusts transporting snow into the bowl via cross-loading pattern. Loading didn’t seem to be significant during my tour. Colder temperatures ATL: puffy and winter gloves.
Snowpack: Red Lady Glades: BTL-heavier moisture laden snow which was like skiing wet powder on southern aspects in Tahoe in February and March.

 

Photos:

Date of Observation: 02/19/2021
Name: Eric Murrow Zach Kinler

 

Zone: Northwest Mountains
Location: Elkton Hills
Aspect: South East, South, South West
Elevation: 9,400′ – 11,200′

 

Avalanches: While on pavement observed a small, fresh Wind Slab in Red Lady Bowl and a large avalanche above treeline on SE slope of Timbered Hill.
Weather: Partly cloudy to mostly cloudy skies along Ruby Range with a few snowflakes and generally light winds below treeline. Snow transport observed above treeline throughout the day.
Snowpack: Traveled across some sunny slopes between 10k and 11.2K. No signs of instability observed with supportive snowpack to skis and boots. Dug a couple of test profiles on southerly slopes in the area (see photos). Test results suggested stubborn or ‘hard to trigger’ results. Slabs were generally 100cm or greater in thickness above concerning weak layers. One test profile was adjacent to a deep natural avalanche from last weekend with PST 90/125 end result in a previously drifted portion of the slope. The weak layer was slightly moist and rounding at two locations where buried 100cm or deeper. Collapsing deeply buried crusts seems to be possible at a thin spot in the slab, but far from likely through this terrain. Southerly slopes had dry surfaces in terrain traveled.

Photos:

 

Date: 02/19/2021

Author: Jack Caprio

Zone: Crested Butte Backcountry

 

 

3 separate loading events produced some impressive avalanches. Check out the full weekly recap here.