Weak layer

CB Avalanche Center2019-20 Observations

Location: Crested Butte Area
Date of Observation: 02/12/2020
Name: Sam ONeil
Subject: Weak layer
Aspect: North East
Elevation: 10500

Weather: Snowing broken skies 24°

Snowpack: 200cm

Facet at 140 and 170

STM at 140 and 170
CTM 28 at 140
ECTX no fracturing

Large Persistent Slab In Kebler Pass

CB Avalanche Center2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 02/11/2020
Subject: Large Persistent Slab In Kebler Pass
Aspect: West
Elevation:

Avalanches: 2 large persistent slabs triggered by 18# explosives on a west facing slope in Robinson Basin. 1F hard slabs failing on F-hard 3-5mm facets. Crown Lines were around 140cm deep.

Mountain Weather for 11,000ft. Wednesday 2/12

CB Avalanche CenterWeather

Date: 02/12/2020

The clear sky overnight will start to increase with clouds today. We are sitting under cool northwest flow, with a small storm forecasted to clip through Northern Colorado Today. It looks like we’ll again be on the edge of that moisture. Models are suggesting that we’ll see partly to mostly cloudy sky cover by the afternoon with a dusting of new snow possible. Wind speeds will also increase a notch today as stronger winds aloft move over the area for the next 24 hours.

Thursday will be another transition day, but this time we’ll be transitioning back to the dry side of the line. We’ll still be under northwest flow through most of the day, with winds and cloud cover decreasing through the day. A dry high-pressure ridge will be building in for Friday. Unsettled weather looks to move back in for the weekend, but nothing to significant looking at the moment.

  • Today

    High Temperature: 21 to 25
    Winds/Direction: 10 to 20/NW
    Sky Cover: Partly Cloudy
    Irwin Snow: 0 to 2
    Elkton Snow: 0 to 1
    Friend’s Hut Snow: 0 to 1

  • Tonight

    Low Temperature: -2 to 2
    Winds/Direction: 10 to 20/WNW
    Sky Cover: Partly Cloudy
    Irwin Snow: 0 to 1
    Elkton Snow: 0 to 1
    Friend’s Hut Snow: 0 to 1

  • Tomorrow

    High Temperature: 24 to 28
    Winds/Direction: 7 to 17/WNW
    Sky Cover: Partly Cloudy
    Irwin Snow: 0
    Elkton Snow: 0
    Friend’s Hut Snow: 0

Baxter Basin avalanches

CB Avalanche Center2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 02/11/2020
Name: MR
Subject: Baxter Basin avalanches
Aspect: North, North East, East, South East, South, South West
Elevation: 9,600-12,000

Avalanches: See photos. Countless small loose dry avalanches, and some storm slabs along mineral point, augusta, richmond ridge, daisy pass, and Schuykill areas, involving the new snow that fell sunday night-monday afternoon. Possible two large avalanches, one off southeast face of augusta, and one off North face of Schuykill that ran into the flats of Baxter Basin, that probably ran during or after the big friday storm event and the new snow fell on top of the debris, so it was hard to say how deep they failed.

We triggered one noteworthy wet loose release while descending the southeast flank of Cascade, which ran with energy a couple hundred feet, entraining surrounding snow but not gouging into lower layers. No photo, sorry!

Weather: The sun was doing its thing today on sunny slopes, warming the snow but not to the point of any roller balling that we witnessed.

Cement Creek

CB Avalanche Center2019-20 Observations

Location: Cement Creek Area
Date of Observation: 02/18/2020
Name: Evan Ross & Eric Murrow
Subject: Cement Creek
Aspect: East, West
Elevation: 9,000-11,200

Avalanches: The 2/7 natural avalanche cycle produced a good number of avalanches in Cement Creek. Most of the avalanches we saw were at below treeline elevations on both easterly and westerly terrain. Most of those were in the small category given the size of the terrain and depth of slab, while a few were reaching D2 in size. The largest avalanches that were observed were on easterly near treeline slopes.

Weather: Clear or few clouds baby. Lovely day out there and we definitely stayed on the dry side of the line. The sun was warming the snow surface on southerly facing slopes and a new crust will form on those lower elevation southerlies. Calm winds.

Snowpack: Traveled on a variety of aspects but primarily east and west. We were targeting some near treeline slopes but in the end got held up below treeline. Both aspects had ~30 to 40cm soft slabs over a weak and unsportive old snowpack. This snowpack structure, plus the old natural avalanches led to little confidence in the snowpack. However, we found basically no results snowmobiling through test slopes. A few shooting cracks were observed but they only extended 10 to 15 feet at best. No collapses were noticed and we certainly were effecting the weak layer. While we didn’t find notable results, I still wouldn’t put much trust in that snowpack on upper 30-degree terrain and especially at higher elevations with previous wind-loading.

Lower Wolverine Basin

CB Avalanche Center2019-20 Observations

Location: Crested Butte Area
Date of Observation: 02/11/2020
Name: Ammon
Subject: Lower Wolverine Basin
Aspect: North, North East, East
Elevation: 9,000′-10,200′

Avalanches: Observed an old avalanche in the upper Wolverine Trees, above the Gunsight Pass Road that ran almost to the road. Slightly filled in but likely ran during the last cycle. NW aspect NTL, D2.

Weather: Sunny but cold on anything but South aspects and valley bottom.

Snowpack: No signs of instability noted. Skied N and NE aspects 25-35 degree slopes. Excellent skiing.
10,100′ NNE in lower Wolverine Basin, HS 156cm, 21 degree slope. ECTN 13 down 39cm on 2/4 interface, 1F slab on 4F+ 1mm FC which are showing signs of rounding. Other layers still visible but all 1F FC and rounding. Will email photos.

Mountain Weather for 11,000ft. Tuesday 2/11

CB Avalanche CenterWeather

Date: 02/11/2020

The Closed-Low down in Arizona is still pushing a little moisture into Southern Colorado. We’ll continue to see some of that moisture pushing into our area in the form of clouds and possible light snow. Winds have died off since yesterday. We’ll see any lingering winds transitioning from SW to NW today as we slide into dry NW flow throughout the day. A little clipper of a storm will be passing by our area Tuesday night and we may again see some clouds and the possibility of very light snow if that sags over our area. On Thursday we’ll start drying out by the afternoon under a building high-pressure ridge and also see an uptick in wind-speeds as the pressure gradient in the NW flow tightens.

  • Today

    High Temperature: 23 to 27
    Winds/Direction: 5 to 15/WSW
    Sky Cover: Partly Cloudy
    Irwin Snow: 0 to 1
    Elkton Snow: 0 to 1
    Friend’s Hut Snow: 0 to 1

  • Tonight

    Low Temperature: 1 to 5
    Winds/Direction: 5 to 15/NW
    Sky Cover: Partly Cloudy
    Irwin Snow: 0
    Elkton Snow: 0
    Friend’s Hut Snow: 0

  • Tomorrow

    High Temperature: 21 to 25
    Winds/Direction: 10 to 20/NW
    Sky Cover: Partly Cloudy
    Irwin Snow: 0 to 2
    Elkton Snow: 0 to 1
    Friend’s Hut Snow: 0 to 1

Below treeline snow favored area

CB Avalanche Center2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 02/10/2020
Name: Eric Murrow
Subject: Below treeline snow favored area
Aspect: North East, East, South East
Elevation: 9000′ – 10400′

Avalanches: none observed

Weather: Overcast skies, light continuous snowfall, and light winds near valley bottom. Visibility was obscured but I could hear some strong winds up high; in the afternoon observed lots of blowing snow on Whetstone around 400pm.

Snowpack: Traveled through below treeline terrain checking out the upper snowpack and more specifically the 2/3 interface that was buried by last week’s healthy accumulations. On E and NE slopes there is around 40cm settled snow resting on top of 1-1.5mm facets. The slab is up to 1f hardness. Snowpack tests revealed moderate propagating results. Stomped and snowmobiled on numerous short test slopes without signs of instability although slopes were small and well supported.
Took a peak on a SE facing slope testing the same interface and got similar moderate propagating results. Oddly enough slab failed on top of the 2/3 melt/freeze crust even though weak facets were present directly below the crust. I experienced one small collapse on a SE slope, but it was not particularly loud and did not produce a crack; I suspect this was the uppermost crust that formed on 2/8 not the more concerning crust from 2/3.
New snow accumulations resting above the 2/8 interface were pushing 6 inches as of 230pm.

Photos:

Mt. Emmons

CB Avalanche Center2019-20 Observations

Location: Crested Butte Area
Date of Observation: 02/10/2020
Name: ADB
Subject: Mt. Emmons
Aspect: South East, South, South West
Elevation: ATL, BTL, NTL

Avalanches: Due to poor visibility, I could not observe any avalanches

Weather: Light to calm winds BTL. S1 snowfall for the tour. NTL and ATL: moderate to strong winds with copious amounts of snow cross-loading Red Lady Bowl. Obscured skies. Blustery on the south and summit ridge. Temperatures were warm enough that removing skins could be done calmly despite the strong winds.

Snowpack: 2 to 4 inches of new snow in last 24 hours. BTL skin track had 1 cm (<0.5 inches) of new snow, while skin track at NTL was filled in with 5 cm (2 inches) of wind transported snow. Thanks Dawn Patrol crew!!
Snow in red glades was silky smooth as skis didn’t touch the weekend’s sun crust.