skier triggered storm slab

CB Avalanche Center 2020-21 Observations

Date of Observation: 05/04/2021
Name: Mark Robbins

Zone: Northwest Mountains
Location: Northwest Bowl Anthracites
Aspect: North
Elevation: 11,200

Avalanches: unintentionally triggered r1d1? wet storm slab at the obvious convexity of NW bowl at about 1:30pm, ran with energy, certainly enough to take you for a ride, not quite enough volume to bury. See photo
Weather:
Snowpack:

Photos:

Sensitive soft slabs

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/23/2021
Name: Zach Guy and Eric Murrow

Zone: Southeast Mountains
Location: Copper Creek
Aspect: West, North West
Elevation: N/ATL

Avalanches: We found sensitive storm slab conditions today at upper elevations. Numerous thin soft slabs released naturally this morning, and we ski cut a handful of similar slabs. All of the slabs were small in size: most were 2″ to 4″ thick, 10 to 20 feet wide. In wind drifted areas, slabs were up to 8″ thick. In sustained steeper terrain, slides ran up to 1500 vertical feet.
Weather: Pulses of moderate to heavy snowfall between periods of quiet weather. Some moderate gusts with wind transport at higher elevations.
Snowpack: About 3″ of new since yesterday.

Sprinter

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/17/2021
Name: Andrew Breibart

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

Avalanches: NA
Weather: Mostly cloudy and calm. On skate out, intermittent S-1 snowfall.
Snowpack: 4 inches of 12 hour snow in CB South at my house at 6:30 AM.
<2 inches of new snow at trailhead and <1 inch of new snow on ridge line of Anthracite Mesa. Snow in the bowl was 100% supportive spring snow.
Bare areas are appearing around trees with expansive branch system that extends outward from the trunk.

Gothic 7am Weather Update

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/14/2021
Name: billy barr

Zone: Southeast Mountains
Location: Gothic
Weather: Scattered light snow Tuesday and overnight into Wed. with just 1½” new snow and 0.15″ of water. Snowpack sits at 28″, up 1″ from the year’s low. The snowpack did not harden much overnight so could get quite rotten if we get decent sun as there was a bit of clearing starting just before sunrise. Breezy overnight and currently around 3-6 mph SW. Not much to write about but it is the heaviest snow ‘storm’ this month so far.

Tipsy cornices!

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/11/2021
Name: Ben A

Zone: Southeast Mountains
Location: Wolverine Ridge
Aspect: East
Elevation: ATL

Avalanches: Skier triggered very small wet looses on E aspects, and very small dry looses on due north. Both confined to very steep terrain.
Snowpack: Cornice about 100 yards long pulling way back from the Wolverine Ridge. See photos, pretty cool if you’re on the right side of it.

Photos:

crusts, corn, slides

CB Avalanche Center 2020-21 Observations

Date of Observation: 04/07/2021
Name: Mark Robbins

Zone: Northwest Mountains
Location: upper slate drainage

Avalanches: Not sure when these ran or if they’ve already been documented. North end of Schuylkill ridge, probably ENE facing? And Purple Ridge near Poverty Gultch, SW facing. See photos.

Weather: Windy AF up high, in and out of clouds, cool air temps

Snowpack: Skiing just before noon, South facing at 12,500 showed minimal signs of softening. By 12,000 the top inch was soft. By 11,500 and SE exposure we got into full corn, 2-3 inches of soft snow. Mushy but still supportive by 10,500 at 12:15.

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:

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: