Punchy Cement Creek

CBAC 2020-21 Observations

Date of Observation: 04/06/2021
Name: Eric Murrow Zach Kinler

 

Zone: Southeast Mountains
Location: Cement Creek drainage
Aspect: East, South East, South, South West, West, North West
Elevation: 9,000′ – 11,400′

 

Avalanches: Several gouging loose avalanches below treeline on east and west aspects (see photos). Views into the upper elevation terrain of Brush and Cement Creeks revealed far less recent wet avalanche activity than areas closer to Crested Butte. Did not observe any obvious Wet Slab activity, even on terrain features that had the same characteristics of observed Wet Slab avalanches nearer to Crested Butte.
Weather: Mostly clear skies transitioning to partly cloudy by mid-day. Moderate westerly winds at ridgetop. Temperatures cooled throughout the day.
Snowpack: Traveling on snowmobiles in the AM was fairly straightforward off-trail with minimal trenching, but as the sun softened, but never fully broke down, surface crusts in the afternoon, snowmobiling off-trail became a challenging task with relentless trenching. Traveled off-trail at 11,100′ and produced a collapse that traveled about 150′ causing around an inch or so of vertical displacement in the snowpack (see photo). Boot penetration in this area was consistently to the ground (see photo). Ski penetration was mostly supportive on surface crusts.

Dug a quick profile on a northwest aspect at 10,800′ with a depth of 100cm (similar snowpack to large collapse) and found meltwater had descended around 50cm down stopping just short of the weak bottom half of the snowpack. The upper 50cm of the snowpack was composed of a 15cm surface crust with 35cm of 4f+ slab (with ice columns present) resting on weak, moist depth hoar. I performed an extended column test and it failed on isolation. The bottom half of the snowpack was moist but did not appear to have been flooded with meltwater yet. Surface crusts on all terrain traveled remained intact during the day; some softened on sunny aspects, but a thin “egg shell” remained which helped to limit Wet Loose avalanche potential. Shoulder and shady aspects below treeline continue to have enough slab structure in the upper snowpack to present future Wet Slab concerns once the meltwater faucet turns back on.

 

Photos:

More wet avalanches

CBAC 2020-21 Observations

Date of Observation: 04/06/2021
Name: Eric Murrow Ben Pritchett

 

Zone: Northwest Mountains
Location: Slate River corridor to Angel Pass area
Aspect: North, North East, East, South East, South, South West, West, North West
Elevation: 8,900′. – 11.600′

 

Avalanches: Numerous recent wet avalanches on northeast through east through south through west aspects. Many were small, but some were large, gouging Wet Loose avalanches. A couple of recent Wet Slabs were observed as well. Two fresh avalanches occurred today on northeast slopes of Schuylkill Ridge – a full-depth Wet Slab below treeline and a gouging long-running Wet Loose avalanche.
Weather: Very warm temperatures with thin high clouds passing by through early afternoon. Light winds from southwest below ridgetop.
Snowpack: Spring transition is well underway, with no dry snow observed on any snow surfaces. Near treeline on a north facing slope, we found about 2 inches of wet polycrystals on the snow surface, with a moist snowpack below that showed signs of yesterday’s meltwater percolating down around a foot and a half deep. The recent meltwater was frozen into widespread horizontal ice lens, likely around old melt-freeze crust buried in mid March. We dug a profile adjacent to a 48 hour old Wet Slab avalanche. The avalanche and our test profile were located on steep southeast-facing slopes with signs of light wind-loading. We measured a 230-300cm deep snowpack. The top of the crown was around 12,000′ and our profile was at a similar elevation to the middle portion of the slab that released (~11,700′). We found a pooled layer of meltwater 50cm below the snow surface that had spread horizontally through an old layer of large-grained facets below a melt-freeze crust. This layer corresponded to depth of the avalanche’s flanks. The slab broke deeper (up to ~100cm) near the crown, higher on the slope. Snowpack tests were not relevant as too much water had flowed through the snowpack since the avalanche released. Generally, the snowpack was pencil hard, with a few harder layers of frozen melt water. We couldn’t determine the hardness of the wetted weak layer since it was a frozen mixture of previously weak facets, an old crust, and newly frozen horizontal and vertical ice masses.

 

Photos:

Evening avalanche obs

CBAC 2020-21 Observations

Date of Observation: 04/04/2021
Name: Zach Guy

Zone: Southeast Mountains
Location: Road tour
Aspect: West

Avalanches: A handful of additional D2’s that ran late in the day on westerly aspects, both wet slabs and wet loose. See photos for details.

Photos:

Dirty diaper obs. 3 p.m.

CBAC 2020-21 Observations

Date of Observation: 04/04/2021
Name: Zach Guy

Zone: Southeast Mountains
Location: Snodgrass TH

Avalanches: See photos. Continued large wet activity. Numerous D1.5 to D2.5 since yesterday’s visit to the same location at 4 p.m. Some may have run late yesterday, most likely ran today. In shallower terrain, there were more wet loose gouging to the ground and a few pulled out narrow wet slabs. Otherwise, more surface sluffs.
Weather: Mix of sun and clouds may have kept surfaces a bit cooler. Warm temps, calm winds below treeline.
Snowpack: Poor refreeze. Ski and boot pen was to the ground this afternoon on below treeline slopes.

Photos:

Gothic debris pile

CBAC 2020-21 Observations

Date of Observation: 04/03/2021
Name: Zach Kinler

Zone: Southeast Mountains
Location: Gothic
Aspect: South West, West

Avalanches: Fresh wet debris pile below the west side of Gothic, ran late this afternoon. Estimated D2.5

Photos:

Wet activity ramping up

CBAC 2020-21 Observations

Date of Observation: 04/03/2021
Name: Zach Guy

Zone: Northwest Mountains
Location: Anthracite Range and driving tour
Aspect: North, North East, East, South East, South
Elevation: 9,600 – 12,200

Avalanches: See photos. Large wet avalanche activity on the rise. We noted numerous natural D2 wet loose avalanches on all but due north aspects and at all elevations. Many of these gouged deep into the snowpack. Some ran today, some yesterday. Several large wet slabs, generally D2 in size, ran today. The one off of the east face of Gothic may have been up to D3 given the long runout (which was obscured from view).
Weather: Africa Hot.
Snowpack: We found frozen surfaces this morning and good corn skiing on due south aspects until about noon, at which point ski and boot pen quickly detoriated. On an east aspect below treeline around 1 p.m., we were triggering large pinwheels that gouged 12″ to 18″ deep. The most active aspects for wet activity were east and northeast where we traveled, but we left before westerlies had their fair share of sunshine.

 

Photos:

Wet Slab Star Peak Zone

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/02/2021
Name: Ben A

 

Zone: Southeast Mountains
Location: Star Ridge above Friends Hut
Aspect: South
Elevation: ATL

Avalanches: Wet slab triggered by wet loose late afternoon 4/2. Wet slab triggered below the rock band. Debris ran over the bench and triggered another wet slab.

Photos:

2:30 PM avy obs

CBAC 2020-21 Observations

Date of Observation: 04/03/2021
Name: Zach Kinler
Location: NW/SE Mountains
Aspect: East, South East, South

Avalanches: Mineral Point had several small loose wet avalanches ATL on the South face and several large loose wet avalanches ATL on the East face. A couple of these were long-running with one gouging to the ground in spots and running to valley bottom. On Baldy, ESE ATL a wet loose initiating from a rock band triggered a wet slab mid slope. One other long-running and gouging wet loose was spotted on an ESE aspect NTL above Copper Creek.
Weather: Hot AF.

 

 

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Late day wet snow check-in

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/02/2021
Name: Ben Pritchett

 

Zone: Northwest Mountains
Location: Roadside observations around Crested Butte. Late day wet snow check-in. Assess depth of melt-water infiltration in relation to potential Wet Slab avalanche problems.
Aspect: North, North East, East, West, North West
Elevation: 10,000

Avalanches: Photo 1: A wet snow surface on a mostly dry snowpack at 10,000′ on a northeast-facing slope. April 2, 2021.
Photo 2: A pattern of small natural avalanches on southeasterly-facing slopes near and above treeline. April 2, 2021
Photo 3: A small natural avalanche on a south-facing slope above treeline. April 2, 2021
Photo 4: An example of an easterly-facing slope that could become dangerous without a freeze at mid-elevations.
Photo 5: A pair of recent slab avalanches that ran on the east to northeast-facing slopes off the Ruby/Owen ridge, and Scarp Ridge.

Estimate* 3/29/21- 1- >TL- E-C-N-R1-D1
Estimate* 3/29/21- 1- >TL -SE-C-N-R1-D1
Weather: Ridgeline Wind Speed: Calm
Wind Loading: None
Temperature: 53 F
Sky Cover: Few
Depth of Total Snow: 120 cm
Weather Description: 53 degrees at 10,000′ at 3pm.
Snowpack: Near 10,000 feet, on northwest through north to northeast-facing slopes, the snowpack was mostly dry, with meltwater draining down only around 10cm so far. Below and near treeline, the shoulder aspects of east and west look the closest to developing a Wet Slab avalanche problem. The steeper southeast through south to southwest-facing slopes are wetted to the ground and melting out quickly. At the Butte snotel at a similar elevation, it did not freeze Thursday night, and it may not again tonight (Friday night). In the worst case rocky terrain features rocky with a shallow snowpack, human-triggered Wet Slab avalanche may become possible by late afternoon Saturday. If there’s another night without a freeze on Saturday, natural Wet Slab avalanches might run Sunday.

 

Photos: