Carbon Peak

CB Avalanche Center2020-21 Observations

Date of Observation: 03/31/2021
Name: ben Pritchett

Zone: Northwest Mountains
Location: Carbon Peak
Aspect: North, North East, East, South East, South
Elevation: 9-11,000′

Avalanches: The slow trickle of large avalanches continues. In Whetstone Mountain’s Hidden Lake bowl, a broad (~250′ wide) section of very large cornice released around 12,200′ and triggered a Persistent Slab avalanche that broke at the ground on a northeast-facing slope. The avalanche looked fresh.

Weather: Chilly start following a strong freeze, warmed to just above freezing. Calm, and clear.

Snowpack: Near and below treeline south and southwest facing slopes have previously drained water to the ground. Little concern for future Wet Slabs. East to southeast-facing slopes near treeline could still pose a near-term Wet Slab concern. Thin slabs (30-70cm deep) rest on presently moist facets. Recently the meltwater has stopped within the slab, but if the melt rate picks up quickly these aspects would be most concerning first. North of east both near and above treeline I found a dry snowpack. Where the snowpack was deeper, the slab was fairly supportive and strong. Triggering a Persistent Slab avalanche remains unlikely, but consequences remain ugly. On these slopes with a dry snowpack, shallow areas remained spooky. In areas with less than around 3 feet of snow, boot penetration would go to the ground. I didn’t experience any collapsing, but I did two ECT’s and both produced hard propagating results on faceted weak layers, one at the ground, one in a very weak layer of large facets below the March storm snow.

 

Photos:

snow survey at bottom of red lady glades

CB Avalanche Center2020-21 Observations

Date of Observation: 03/31/2021
Name: Andrew Breibart

Zone: Southeast Mountains
Location: Snow course-Keystone
Aspect:
Elevation: BTL

Weather: calm, clear, and below freezing before 9AM

Snowpack: snow depth is 34 inches and snow water equivalent is 10 inches.
melt freeze crust. in the shade there was a trace of recent snow on melt freeze crust. Snow was fully supportive on skis and ski boots. at one sample point, we found an ice layer but not an ice lens 6 inches from the ground.

Windy!

CB Avalanche Center2020-21 Observations

Date of Observation: 03/29/2021
Name: Jack Caprio

Zone: Southeast Mountains
Location: Mount Emmons
Aspect: North, North East, East
Elevation: 9k-12.5k

Avalanches: Small wet loose activity on east-facing slopes of all elevations. SW and W facing slopes had more wet loose activity below treeline due to winds keeping alpine surfaces cool. NE below treeline got in on the action too in the happy chutes (see photo).

Weather: Few clouds. Warm temps below treeline. The alpine was very breezy with consistent moderate SW winds along with strong gusts.

Snowpack: Isolated 2-5 inch wind pockets on NE and E facing terrain near ridgeline. Previous tracks from yesterday in a steep alpine chute had been erased overnight due to wind-loading. Although the wind slabs were very small, it was still enough of an issue for us to avoid a very steep, exposed, slightly cross-loaded chute. We chose to descend a steep, planar north-facing slope away from any ribs or other features prone to cross-loading. There were no signs of instability on our descent.

The snow stayed dry on due north slopes. Below treeline NE-E facing slopes became moist by early afternoon as expected.

 

Photos:

Ripe Cornice

CB Avalanche Center2020-21 Observations

Date of Observation: 03/27/2021

Zone: Northwest Mountains
Location: West Elks
Aspect: South East, South
Elevation: 12,000′

Avalanches: Other than some smaller sheds of recent snow attributed to solar warming below rock bands and such, no recent notable avalanches observed. While traversing the ridge to access our ski line, my partner put a left ski just a little to far out on a big cornice and punched through far enough to trigger a school bus-sized cornice fall. The ridge is very sharp (knife ridge) in this particular spot and his right ski didn’t leave bare rock on the windward side of the cornice when it failed. Fortunately, my buddy was in a safe enough location to not take a ride, but it was certainly a sobering reminder to give every cornice it’s due respect and always ensure you are in a safe place when negotiating the beast. It was a big cornice failure and entrained localized snow on it’s descent, however, it didn’t propogate much beyond the immediate path. Probably ran around 1000′. This cornice, as I assume most are currently, was primed and ready to go. The pictures come from my flip phone, so I apologize for the poor quality.
Weather: Ridge winds were moderate from the North. Pretty pleasant on the climb to the ridge. Lots of sun.

 

Photos:

Anthracite Mesa-Coneys

CB Avalanche Center2020-21 Observations

Date of Observation: 03/27/2021
Name: Andrew Breibart

Zone: Southeast Mountains
Location: Washington Gulch-Coneys
Aspect: North East, East
Elevation: BTL

Avalanches: NA-poor visibility
Weather: Obscured skies with S1 and S2 snowfall. Calm. On the skin out, obstructed skies, calm and intermittent S-1 snowfall.
Snowpack: Supportive snowpack valley bottom to the ridge. 48-hour snow: 3 to 6 inches with 8 inches on the leeward side of the ridge line. New snow seems to be bonding to the last melt freeze crust. Triggered shallow storm sluff at the convex entrance to first bowl.

 

Snodgrass Profiles

CB Avalanche Center2020-21 Observations

Date of Observation: 03/24/2021
Name: Ian Havlick

Zone: Southeast Mountains
Location: Snodgrass Frontside
Aspect: North, North East, East
Elevation: 10,200-11,500

Avalanches: none
Weather: BKN moved to OVC with S-1 snow showers late afternoon. no accumulation. temperartures 20-28F. Mostly calm.
Snowpack: I dug 12 full profiles today for a CU researcher BTL snodgrass, N-E aspects. No stability tests as I was collecting density data in treed terrain, but still same poor structure, P-hard slab above 20-40cm 2-4mm F+ DH. has improved a bit from same locations dug 1 month ago, F- DH then, compared to F+ DH now, but still weak, and stiffer slab. General HS in areas dug between 11, 200 and 10,000 was 90-130cm.

Small persistent slab

CB Avalanche Center2020-21 Observations

Date of Observation: 03/24/2021
Name: Jack Caprio
Zone: Southeast Mountains
Location: Lower Slate
Aspect: North, North East
Elevation: 9k-11k

Avalanches: Intentionally ski triggered a small persistent slab avalanche on a wind-loaded feature just off a road cut. The avalanche broke in two places: On the most recent interface about 10-15 cms down from the surface, and on the 3/10 interface which was buried about 40 cms.

Weather: Overcast and warm.

Snowpack: I stayed below treeline all day near the border of the NW and SE zones. In the protected areas where no wind loading has occurred the snowpack is very weak top to bottom. Generally, no slab avalanche concerns on protected northerly slopes due to lack of a slab in this area. As I stepped out into open skied, wind-affected areas slabs became more common. Slabs were generally soft but did reach 1F hardness just above the 3/10 interface on the slide I triggered. The 3/10 interface consists of 1-1.5 mm facets on due north slopes in this area.

Photos:

Scarp Ridge, Elk Basin, Redwell, Red Lady Bowl

CB Avalanche Center2020-21 Observations

Date of Observation: 03/22/2021
Name: Ian Havlick

 

Zone: Southeast Mountains
Location: Scarp ridge/Indy Basin/Elk Basin/Mount Emmons
Aspect: North, North East, East, South East, South, South West, West
Elevation: 9000-12,400

 

Avalanches: No avalanches observed except for an older crown line in NW facing ATL Peeler Basin off Scarp Ridge
Weather: Mostly clear skies gave way to mostly cloudy and poor visibility due to convective S1-S2 snow showers. heavily rimed snowfall, 1/2″ accumulation during these showers.
Snowpack: Snowpack was mostly quiet, mix of 2-6″ new snow over the last 48hrs resting on mix of crusts, windbuff and small grained facets. Some minimal windloading on south facing ridgelines from early morning northerly winds. No signs of instability across variety of aspects. No significant windslab development.

 

Skier Triggered Wind Slab

CB Avalanche Center2020-21 Observations

Date of Observation: 03/21/2021

Zone: Northwest Mountains
Location: Peeler Basin
Aspect: North, North East
Elevation: 12,100’

Avalanches: Skier triggered (D2?) wind slab off ridgeline ATL on northeast aspect. Obvious convex rollover and poor terrain selection. Crown approx 2’ and stepped down mid-slope to 3/10 layer. Skier was not caught and able to ski out but pretty spicy!
Weather: Mixed snow and sun. Maybe accumulated 1-2” during the day. Very calm wind.
Snowpack: 6-8” new above 11k. Seemed generally non-wind affected until obvious loading on ridgeline. Solar aspects became very moist with each sun pop throughout the day.

 

Photos: