Observations

Zone: Northwest Mountains
Date of Observation: 12/18/2020
Aspect: East

Avalanches: 3, D1.5 to D2 Natural Persistent Slab Avalanches. East Aspect, below treeline.

Zone: Northwest Mountains

Location: Anthracites: Friendly Finish

Date of Observation: 12/18/2020

Name: CBAC

 

Subject: Preliminary Report on Anthracite Fatality

Aspect: North East

Elevation: 10,580 feet

Avalanches:

A solo skier was caught in a large slab avalanche while descending a run known as “Friendly Finish” in the Anthracites. The skier did not survive the avalanche.

Preliminary observations suggest that the slab avalanche was several feet thick, likely breaking on a layer of old, faceted snow that was buried about a week ago.  Previous to descending the victim spoke with a group of two skiers who were also traveling in the area. When the two skiers completed their descent and returned to their parked snowmobile they found the victim’s snowmobile parked without any sign of him. They snowmobiled to a place where they could see the slope he told them he was planning to descend and saw a fresh avalanche. They located the victim with a transceiver search and extricated him from the debris. Tragically he did not survive the event.

The CBAC and CAIC will be conducting an accident investigation tomorrow.  More details on the incident are forthcoming.

Weather:

Snowpack:

Photos:

Zone: Northwest Mountains
Location: Pittsburg area
Date of Observation: 12/18/2020
Name: Zach Kinler

Aspect: East, South West, West, North West

Elevation: 9,400-11,200′

Avalanches:

Observed 2 small fresh slab avalanches mid-slope on easterly facing terrain features on Schuylkill Ridge.

Several shallow wind slabs off a southerly flank of Gothic Mt.

 

Weather: Cold start with snow showers tapering off. Felt the warmth midday with the sun peaking out for a few hours. Low-level clouds were drifting by keeping the Ruby Range and points north in the clouds.

Snowpack: 10″ new snow. Toured on primarily West aspects below tree line. Got lots of feedback from the snowpack with collapses in the flats, in the trees and shooting cracks/shattering on slopes up to 35 degrees that had not already failed. The weak layer is 15-25 cm of large grain facets and crust/facet combos near the ground (depending on exact location).

Got a look at a few steep easterly slopes which had previously avalanched however that evidence was not very obvious. On slopes that had slid, was only able to get a bit of loose surface snow on slopes greater than 37 degrees to move as these paths refill. Light to moderate WNW  winds were moving small amounts of snow onto leeward aspects near tree line. Rest in Peace, JS

 

 

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Zone: Crested Butte Backcountry
Date: 12/18/20
Name: Jack Caprio/ Zach Kinler

 

 

For the first time in over two weeks, we got some snow! With the new snow falling on our very weak snowpack, widespread natural and human triggered avalanches were a common theme of the week. Here is the summary of all avalanche and weather activity over the past week

Zone: Northwest Mountains
Location: Anthrcites
Date of Observation: 12/17/2020
Name: Kirk Haskell

Aspect: North East
Elevation: 11629

Avalanches: No signs of recent activity

Weather: Calm and cold

Snowpack: There were no signs of instability. Wind had taken it’s toll in open areas. East Bowl was almost blown to bare ground. Still bit thin out there , more snow please.

Zone: Northwest Mountains

Location: Slate

Date of Observation: 12/16/2020

Name: Zach Guy

 

Subject: Collapse city

Aspect: North, North East

Elevation: N/BTL

Avalanches:

Triggered a couple small persistent slabs remotely above a creek bed. Appeared to be a fresh D2 natural slab off of a westerly gulley of Gothic. Widespread activity from last weekend with numerous crowns 18″ thick spanning entire start zones where we traveled.

 

Weather: Ruby divide stayed in the clouds all day, with scattered skies elsewhere. Light snow at times. Light winds where we traveled, some drifting snow in the alpine.

Snowpack: Dozens of collapses, just about every open slope we came to. Some radiated hundreds of feet. With the exception of a few small pockets, every steep, shady pitch we came to had already slid over the weekend. Persistent slab structure is 2 feet thick at ridgeline and one foot at valley bottom. Stubborn cracking in isolated wind drifts on crossloaded south aspects up to one foot deep. Bed surfaces from the weekend cycle (friable melt freeze crusts a few inches thick over facets) are generally topped by 6” of low density snow.

 

Photos:

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Zone: Northwest Mountains
Location: Anthracites
Date of Observation: 12/16/2020
Name: Mark Robbins

Aspect: North, North East
Elevation: 10,000-11,400

Avalanches: debris noted from AMR sled parking lot coming off the cliffs near east bowl. Didn’t tour out the field to investigate.

Snowpack: widespread surface hoar at all elevations on shady slopes

Photos:

Zone: Northwest Mountains
Location: Paradise Divide
Date of Observation: 12/15/2020
Name: Evan Ross
Aspect: East, South West, West
Elevation: 11,000-11,500

Avalanches: It’s a smorgasbord of natural avalanches out there. The oldest ones are from Friday 12/11, and the most recent ones are from the last 12 hours. The most recent were all wind-related from the increased overnight winds. Avalanche observations from the last 12 hours above treeline: West on Mt Baldy had 2 D2 and 1 D1.5. There was a small dribbler on a Southerly Aspect of Gothic. Red Coon Bowl had a fresh D2 this morning on an East aspect. NE Purple Palace NTL has a suspect D1.5 the could have fit in the last 12 hours too. All these slabs ran on the old faceted snow near the ground. Some may have started on an interface as a windslab, then gouged, but I couldn’t tell from a distance.

Remote triggered 1 D1, from a few hundred feet away, above treeline, east aspect.

Of other particular note. The SW to W slopes of baldy on the way up to P-Divide had a fairly good cycle last weekend. Many of those paths ran, piling on the road and continuing to run below. About 5 R1D2’s.

Weather: Headed out in the afternoon. The sky had cleared to partly cloudy for the few hours I was out. Winds also appeared to decrease and were generally light with moderate gusts. Most of the snow appeared to have already been transported at upper elevations for the recent wind direction and speeds, however, there were still a few snow plumes out there at times.

Snowpack: Just having fun on a personal day and noting the continued obvious signs of instability. Plenty of collapses and shooting cracks while traveling on East and West aspects. All the steeper slopes I got close to were fairly small in size, and well supported. So they simply cracked without much downhill movement. I suspect that some of the wind-board from last weekend, which is now buried, is collapsing into the softer snow below. Also, some of the fresh wind-loaded features are also cracking on non-persistent grains closer to the snow surface. However there are still slopes cracking hundreds of feet away, so those must be collapsing on the November Facets. The average snow depth in the area was about a meter.

Zone: Northwest Mountains

Location: Irwin Tenure

Date of Observation: 12/14/2020

Name: Irwin Guides

Subject: Remote triggered slide at Irwin

Avalanches: Skied the far skiers right side of lodge gully W aspect <TL and remotely triggered from 50′ away a .5 to the ground 50′ wide. SS-AS/u-D.5-G

Weather: Cold morning low of -14. Started snowing at 0700 after a clear night. Sky remained Obscure all day snowing S1/ S-1 off and on all day. Winds were Calm <TL and light out of the S >TL.

Snowpack: Snowpack has settled and become supportive. Ski pen averaged 30cm. The average HS up to 70 ridge was 50-60cm. Toured up the road system to the top of 70 down 70 gully to skin track and Lodge Gully to finish. Observed numerous collapses but nothing not to be expected or too large. Several Obs on Steeper terrain around Irwin village road cuts, etc. had cracked to the ground slumped but did not run. These occurred two days ago near the end of the storm.

Zone: Northwest Mountains
Date of Observation: 12/14/2020
Name: Evan Ross
Aspect: North, North East, West
Elevation: 11,000

Weather: Poor visibility until the weather started to clear in the late afternoon. Calm winds. Measured about 6″ of very light new snow at 11,000ft, from todays storm.

Snowpack: Spent a few hours in the afternoon traveling around 11,000ft on West, North and Northeast aspects. More of the same, shooting cracks on many of the slopes traveled. The avalanche problem was fairly obvious without having to look to hard. Conservative decision making. If you chose to travel on a steep slope, that hadn’t already avalanched, it seemed like a high likelihood it would avalanche… Got close to some bigger steep slopes wondering if they would remote trigger and didn’t see any results.

Measured about 6″ of very light new snow at 11,000ft, from todays storm. HS at 11,000ft in a well sheltered meadow was right about 100cm.