Crown observed in California Bowl on Snodgrass

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 03/24/2020
Name: Nick
Subject: Crown observed in California Bowl on Snodgrass
Aspect: North East
Elevation: 10,700

Avalanches: Observed a couple day old crown that showed signs of wind effect, approx 18in deep and spanning about 40 feet. Ski cutting hangfire produced a small slab pocket about 10ft x 10ft with an 18in crown. Looked to be on the old snow- new snow interface.

Weather: Sunny, partly cloudy

Photos:

Afternoon Look Around Kebler Pass Area

CB Avalanche Center 2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 03/24/2020
Name: Evan Ross
Subject: Afternoon Look Around Kebler Pass Area

This is a story book observation. See photos and descriptions.

M Face Avalanche – Whetstone

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 03/24/2020
Name: Whitney, Syd, and Cheese
Subject: M Face Avalanche – Whetstone
Aspect: North East

Avalanches: Large avalanche on M face of Whetstone! Up close. Skied the Summit bowl and it was awesome! Small signs of instability skinning up the ridge between Summit Bowl and M face, some cracking and one collapse. Beautiful Day!

Weather: Mostly sunny, intermittent clouds with L winds.

South side of Baldy

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 03/24/2020
Name: Zach Kinler
Aspect: East, South East, South, South West, West
Elevation: 10,500′-12,000′
Avalanches:

No new avalanches observed

Weather: Pleasant day, Partly Cloudy skies, temperatures warming to near freezing. Calm to light breezes in sheltered areas with Light to moderate westerly wind near tree line.

Snowpack: 5″ new snow around 11K. Up to 11,500′ this snow became moist on the southern half of the compass. Above 11,500′ surfaces were mostly dry with increasing westerly winds transporting snow onto easterly aspects. Small drifted terrain features had deposits up to a foot deep with cracking from skis traveling 10-20 feet. Last week’s crust was around 60 cm below the surface. Avoided larger drifted features in this terrain. Once below 11,500′ warming surfaces limited available snow for transport with similar slopes producing no instabilities. Winds increased after 16:00 with moving snow visible on the highest peaks.

East aspect 11,800′

Moderate westerly winds were transporting snow onto leeward aspects

Winds increased by late in the afternoon moving available recent snow

Gothic 7am Weather Update

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 03/24/2020
Name: billy barr
Subject: Gothic 7am Weather Update

Weather: cloudy and mild with light snow, mostly in the few hours after dark with stronger wind into the night but then letting up by 9 p.m. Total 24 hour snow was 4½” with 0.35″ of water. Snow pack is at 54½” and holding somewhat steady. Currently overcast and calm with the temp. 22F, the low of the day.

Mt Emmons Avalanche Visit

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 03/23/2020
Name: Evan Ross, Zach Kinler
Subject: Mt Emmons Avalanche Visit
Aspect: North East, East
Elevation: 11,800ft

Avalanches: This avalanche is estimated to have released on the morning of 3/22, during a period of intense wind-loading and a pulse of high precipitation rates. The subtle aspect changes along the crown varied from NE to E and the snowpack structure was notably different between those changes. The avalanche was small for the terrain (R1) and large in destructive size (D2), therefore capable of burying a person. We spend our time on the deepest section of crown. The crown in that area average 60cm and was up to 125cm tall. The avalanche failed on-top of two separate crusts. Those crusts were each 2cm thick with the upper being Pencil hard and the lower 1F hard. Where there was the most wind-loading the avalanche failed on the deeper crust, lower on the ridge where there was less wind-loading the avalanche failed on the upper crust. Both of those crusts had 1.5mm facets on top and 1 mm facets below. Those facets were not particularly weak and didn’t produce results in ECT or PST tests from two separate locations along the crown. On the more NE tilted portions of the crown, the crusts faded away, but a thin layer of small rounding facets could still be found. The slope angle near the crown averaged in the upper 30’s and rolled over steeper lower on the slope.

There were some cracks in lower angled sections of the slope above the crown. Though of interest, there were no shooting cracks past the flanks of the avalanche or lower in the bowl where the avalanche debris passed through and came to a rest. The flanks of the avalanche noticeably decreased lower on the slope and below the previous wind-loading.

Gothic Mountain Avalanches

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 03/22/2020
Name: Evan Ross
Subject: Gothic Mountain Avalanches
Aspect: East
Elevation: Above Treeline

Avalanches: This picture tells a really cool story about avalanches and you can definitely look at it for some time. Many old sluffs had run through the terrain without triggering much for avalanches. Then during a period of intense loading Tuesday morning, natural Wind Slab Avalanches started to run and thoughts further stepped down to the 3/18 interface. At least one of these become very large in size.

Photo: David Scheefer

Kebler Pass

CB Avalanche Center 2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 03/22/2020
Name: Zach Kinler
Aspect: North, North East, East, South East
Elevation: 10,200′-11,400′
Avalanches:
Axtel NE 11,600′ D1.5 Wind Slab
Anthracite Range E 11,400′ D1.5 Wind Slab, likely ran 3/20 or 3/21
Elk Basin SE 11,600′ 4 X D1.5 Wet Loose

Weather: Partly to Mostly Cloudy skies with pleasant temperatures, warm in the sun, cool in the shade. Light to moderate westerly breeze, temps near freezing.

Snowpack: Wind was transporting snow on peaks and ridgelines at times throughout the day. North aspect 10,600′ had 60 cm(2 ft) of settled snow since 3/19. Previous crusts were not felt until you moved onto Northeast aspects where they were observed at 60 cm(3/19) and 80 cm. East aspects below 10,500′ had a thin surface crust by end of the day. No signs of instability while skiing E-N aspects up to 40 degrees in sheltered terrain. Southerly aspects were moistened and had refrozen into a soft 3 cm crust by 16:00.

Axtel NE 11,600′

Anthracite Range, E 11,400′

Elk Basin, 11,600′ SE

Old Slabs And Sluffs In The Slate

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 03/22/2020
Name: Evan Ross
Subject: Old Slabs And Sluffs In The Slate
Aspect: North, North East, East, South East
Elevation: 9,500-11,500
Avalanches: Several old avalanches with more details in pictures.

Weather: Southwest to West winds peaked with some intense loading and high snowfall rates this morning as the shortwave was moving out. That loading period lead to several natural avalanches in other observations. By noon the sky cover had started to decreas. Mostly cloudy sky held for the ruby range while less cloud clover apreaded to be down valley. Winds were light were I toured but moderate loading on upper elevation ridgelines and peaks continued through the day. After the peak precip S-1 snowfall continued into the early PM hours.

Snowpack: I went hunting and didn’t find too much for concern. I did back off from climbing through one wind-loaded terrain feature but that was about it. In general, hand pits continued to identify non-persistent storm instabilities in the upper snowpack, and beyond that, those showed no signs of instability. While traveling on the NE to E to SE slopes, 8 out of 10 attempts to find a result on the 3/18 interface showed good bonding at the interface with no concern. While considering climbing through a NE wind-loaded terrain feature at 11,600ft, a quick hand pit reviled a concerning soft crust with a thin layer of weaker faceted snow below. Digging just downslope in a safer area, the same interface was found 75cm’s down. Though the weakness below the crust was not quite as pronounced. A thicker layer of grouple was about 85cm down. ECT results didn’t produce any propagating results on either of those interfaces or in the storm interfaces higher up in the snowpack.

We had to hold a fairly strong north tilt to slopes if we wanted to avoid crust that formed yesterday morning on NE. Ski pen on northerly facing slopes was about 35cm, by the time you hit ESE ski pen was only about 5cm.