Partial burial at anthracites

CB Avalanche Center 2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 12/01/2019
Name: Lee pow

Subject: Partial burial at anthracites
Aspect: North, North East, North West
Elevation:

Avalanches:

Big chute on anthracites. Dropped 3 cornices on big chute from the overhead cornices skiers left at top of run. Most of the gut of the run slid below the first tree band/rollover, 100cm to ground. Proceeded down the run and stopped at first safe zone on skiers right, when I peeled back onto the run, some hangfire caught me and carried me 100 feet, buried to neck. Self rescue.

Dug an ect at the bottom of the run before dropping (thought a lower pit would be more indicative of the line vs digging above)
Lots of spatial variability

Talking to others at the sleds, many cracks were observed everywhere at the cites, but 7th bowl, due to buried weak layer. One crack was reported to move ~4 feet but did not run.

Weather: Clear and cold
Snowpack: About 100cm

Photos: added by CBAC forecast staff on 12/3.  Photos from 12/2 site visit

Whoomphing/collapsing Slate River area

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 11/30/2019
Name:

Subject: Whoomphing/collapsing Slate River area
Aspect: North, North East
Elevation: 10,000-11,000 ft

Avalanches: 

None observed, however we did observe several major collapses and some cracking in flat areas as well as some 30 degree test slopes

Weather: Cold, snowing S1/S2, blowing snow, sustained northwesterly winds with elevated gusts

Snowpack: Thin with nearly no structure below treeline, increasing structure and snow height up to 3 ft near and above treeline with some definite evidence of recent slab formation

 

Still Hitting Rocks

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 11/30/2019
Name: SydD

Subject: Still Hitting Rocks
Aspect: South West
Elevation: 11500

Avalanches:

N/A

Weather: A beautiful overcast day, light snowfall (s1), and blistering moderate winds from the west/southwest. Snow and winds relaxed early in the afternoon, chilly all-day
Snowpack: Traveled across large wind whales, and while accending witnessed loud whupping and a few shooting cracks while skiing. The storm dropped close to 10″, but still a very shallow snowpack. No avalanches to report.

Photos:

SW Pow

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 11/30/2019
Name: Evan Ross

Subject: SW Pow
Aspect: South, South West
Elevation: 11,000-11,500

Weather: I hiked around with 2 base layers, a softshell, a harder shell, and a big puffy with the hood up. Ooo hiked with my goggles on too. That should explain the weather best to us average people. I’m still cold. Maybe I’m just getting soft? Anyway, the down-valley winds were cranking and continuing to drift snow through the day, while the temperatures where cold. The nearby Cinnamon Weather Stations at 12,100ft showed W-NW winds around 30mph and a high temp of 1 degree. Poor vis with obscured to mostly cloudy sky.

Snowpack: Traveled on very specific SW slopes in the 34-37 degree range on average. Line everything up right, and the skiing was great without the avalanche issue on the other side of the compass. Line it up wrong, and the slope could be blown off by the wind, lacking enough snowpack at too low an elevation, or cross-loaded with a 1 to 2ft deep windslab.

Given the variability and the targeted objectives for skiing its hard to generalize a SW aspect at this elevation. Most SW and south slopes around these elevations are holding a thin snowpack without a current avalanche problem. Add in some more specific variables and you could run into a few more issues. The shaded sides of gullies are holding the old weak October snow. The 11/20 crust can be thick and strong on steep slopes, non-existent on lower angled slopes, and of course transitional in between. Next to the wind-slab avalanche problem, this 11/20 crust was the main potential weak-layer to manage. We had plenty of large collapses while traveling from low angled slopes to a steeper slope, or through sparse trees creating a variable snowpack structure.

Coney’s

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 11/30/2019
Name: Eric Murrow & Zach Kinler

Subject: Coney’s
Aspect: North, North East, East
Elevation: 9600′-10,800′

Avalanches: Two avalanches intentionally and remotely triggered from the ridgetop. D1 and D1.5. The bigger remotely triggered avalanche was not enough to bury a person but accelerated and ran about 400 vertical feet. You would have been seriously bunged up if you took this ride.

Weather: OVC, Light and variable winds in sheltered below tree line terrain, moderate WNW winds at ridgetop, intermittent S-1 with less than 1-inch accumulation. Cold with temps in the upper teens.

Snowpack: HS 50-60 cm in sheltered terrain. Very little old snow existed in this non-drifted low elevation terrain near the interior part of the range away from the snow belt. No cracking or collapsing observed on the sheltered skin track. Once on the ridgeline where moderate winds have drifted new snow, we immediately experienced collapses and cracking within the drifted snow. In this area immediately lee of the ridge, the October snow was much more continuous as well due to previous wind loading. Traversing the ridgetop, we were able to trigger two avalanches, D1-D1.5 in size. Once off the ridgeline and below previous and current drifting, signs of instability stopped as the weak layer was more discontinuous and thin.

Photos:

Shattery

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 11/30/2019
Name:

Subject: Shattery
Aspect: North East
Elevation: BTL

Avalanches:

none seen but no vis

Weather: Light snow off and on, moderate wind gusts.
Snowpack: Knee deep in protected N and NE slopes, 6-10 inches total on NE slopes in the open. Plenty of collapsing/cracking on skin up, protected glades in the 30-degree range N/NE shattered upon first turn but no movement.

Photos:

Gothic Townsite 5:30am Obs

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 11/30/2019
Name: billy barr

Subject: Gothic Townsite 5:30am Obs

Weather: Generally steady but light snow overnight with moderate wind as snow continues. So far 3½” overnight with 0.31″ water and for the past 22 hours there has been 7½” with 0.61″of water and snowpack is up to 12″ deep. Wind continues moderate and gusting (4-8 W gusts to 15) with light snow and temperature is 11F with the range since midnight a low of 10F and high of 12F. I will update a bit after 7 a.m. billy

Gothic Townsite 7pm Obs

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 11/29/2019
Name: billy barr

Subject: Gothic Townsite 7pm Obs
Aspect:
Elevation: 9500

Avalanches:
Weather: Quiet through the morning with light snow starting mid day but strong wind. Snow picks up mid afternoon then become heavy as wind stops before snowfall stopping after an hour or so. Wind has died down and snow still on pause. New snow totaled 4″ with 0.30″ of water. Snow pack at 9″. Currently overcast but no snow with generally light wind but occasional strong gusts to 25. Days high was 34F but now dropping at 21F.

If snow starts back up I will try and update early morning, otherwise not until near 7. billy
Snowpack:

Photos:

Cracky and Collapsey

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 11/28/2019
Name: Eric Murrow

Subject: Cracky and Collapsey
Aspect: North, North East, East, South East, South, South West, West, North West
Elevation: 9500′ – 11,800′

Avalanches:

Observed several natural avalanches from the most recent storm on 11/25 – 11/26.

1 x SS on SE aspect of Treasury at approx 12,600′ – D1, looked like a Wind Slab
3 x SS on NW aspect of Baldy (WSC bowl) at approx 12,300′ – D1’s, poor vis but appeared to be very narrow Persistent Slab avalanche (possible loose snow avalanches from rocky area above were able to produce slight propagation as they pushed downslope).

Weather: Mostly cloudy skies with cloud deck nipping at the tops of peaks, no precip, light winds from the south with gusting into the 20’s – minor snow transport but no significant loading observed.

Snowpack: Toured through N and E aspects in open, near treeline terrain (11k to 11800′). HS generally varied from about 20cm to 80cm through this windswept terrain. While moving through easterly terrain we observed numerous collapses on small drifted terrain features. Collapses and resulting cracks were traveling up to 50ft. All of these cracks were failing on the 11/20 interface (old October snow). The slabs remain soft in this wind affected terrain with hand hardness of fist+ and some 4finger (with the exception of sporadic thin, stiff windboard at the surface). A very thin, about 1cm or less, melt/freeze crust was capping the old October snow up to treeline even on northerly slopes. This crust is weak and faceting through. The crust doesn’t seem to be much of an issue because it is thin and the immediate underlying snow so very weak. It will not take much of a loading event before failure.

Dug a test profile on a north-facing site immediately adjacent a small avalanche path with ECTP 5 results on the 11/20 interface. Given the obvious old weak snow and collapsing, this result was not surprising but when we jumped around, in several spots, next to this small avalanche path, we could not get it to collapse. The old faceted grains at the failure interface were generally around 1.5mm to 2mm and extremely weak.

Snow coverage on southeast, south, and southwest slopes in the area visually looked quite shallow.

Photos:

Talkative Snowpack out West

CB Avalanche Center 2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 11/28/2019
Name: Joey Carpenter

Subject: Talkative Snowpack out West
Aspect: North, North East
Elevation: 11400

Avalanches:

None observed. 5 notable collapses and shooting cracks.

Weather: Skies starting OVC and moving to BKN from 930-1300. No precipitation, intermittent light wind from S/SW with no visible transport. Comfortable temps.
Snowpack: HS 75cm of generally unconsolidated, weak snow @11.3k NNE aspect. Bottom 35cm is 1-2mm facets with this weeks storm snow resting on top. We got 3 small/med collapses in this area that were enough to direct us to an alternative route. While slab size/energy was not largely concerning, the potential of being dragged even a short distance through early season ground hazards by a small avalanche was. We dug down after the third collapse at the entrance to a popular run in the area to inspect where failure was occurring (see photo). The new/old snow interface was the culprit.

On our ski, we got two more small collapses in relatively low angle terrain with shooting cracks up to 20 feet (see photo).

BTL SPX is very shallow and weak, even in this snow favored part of the forecast area…snow snakes, downed logs, eye pokers, skin rippers, ski blasters, knee twisters, heel smashers and hat grabbers abound.

Photos: