Afternoon near treeline wet snow

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 04/10/2020
Name: Eric Murrow
Subject: Afternoon near treeline wet snow
Aspect: North East, East, South East, South, South West
Elevation: 9400′ – 11600′

Avalanches: Lots of recent wet avalanche activity around the range. Rustlers Gulch area produced a number of Wet Slab’s the failed in the past couple of days on south and southwest aspects around 12,000′. A couple avalanches were D2 in size.

Weather: Partly cloudy skies in the afternoon with light winds. Felt slightly cooler than the previous day with cloud cover and light winds.

Snowpack: Targeted near treeline slopes that faced northeast, east, and southeast. Moved through terrain between 245pm and 500pm which was a bit too late for peak melt. All sites had developed thin crusts at the surface since the sun had transitioned westward.

On southeast slope at 11,500′ found HS around 150cm with water pooling at the first crust about 40cm down, ECTP 26 beneath the crust with water pooling and above a second crust just a few inches deeper. Another prominent crust was present 50cm above ground with weak, moist 4f snow at the ground. Did not find any ice lens’ lower in profile. Snowpack structure appeared to fit with observed Wet Slab avalanche activity on similar aspects in Rustlers Gulch from the past couple of days.

On an east-facing slope at 11,500′ with HS of 175cm found water pooling on a crust 50cm from the surface. ECTP 21 on the crust with pooled water. Liquid water had just barely pushed beneath this upper crust. Slab structure in the midpack is dense, pencil hard snow.

Shifted to a northeast slope with an HS of 185cm at 11,600′ and found wet snow in just the top few inches of the snowpack. The mid-march interface, 50cm down, was dry on my test wall, but a small portion of the observation wall had an ice lens, but the entire layer had not wetted. I followed ice columns from the surface down and most did not make it to that interface and stopped 10cm short. No results in stability test, ECTX.

Photos:

Teocalli

CB Avalanche Center 2019-20 Observations

Location: Brush Creek Area
Date of Observation: 04/09/2020
Name: Ian Havlick
Subject: Teocalli
Aspect: East, South East, South, South West, West, North West
Elevation: 8500-13000

Avalanches: Observed a variety of wet loose and some gouging and developing wet slab activity, all looked to have run Tuesday or Wednesday during peak warming. Avalanches observed ranged from pushy D1 to D2, but all would have been ugly and dangerous if involved. The most impressive activity was on mid elevation, near treeline to above treeline, east and west-facing terrain, all initiated as wet loose and as they ran, entrained deeper weak layers, some which propagated as slabs. Shallow, rocky terrain most punchy and suspect with wet slab structure and failing easily in hand shears on old, 4-6mm moist depth hoar.

Weather: Clear skies overnight with some thin cirrus moving in mid morning. Temperatures were pretty obviously inverted with lows in the low 20s in valley bottoms, and mid to upper 20s above 11,000ft it seemed. Left the field 12:00.

Snowpack: Snowpack is hanging in there with overnight refreezes to provide safe travel until about 12, past that, ski and snowmobile travel grows more difficult in the shallower parts of forecast area, Brush Creek with tracks augering and skis punching. HS ranged 30-80cm in terrain traveled. Overnight refreeze 2-6″ deep, with still dry winter-like snow deeper in the snowpack. Areas shallower than 40-60cm are isothermal in full meltdown. Got some major collapses both on still frozen uptrack, and on descent, which must have been big to notice on south-facing descent!

Photos:

East facing wet loose propagating into wet slab on ridgeline leading to WSC Mountain viewed from Teocalli, likely ran 4/7 or 4/8
Wet avalanches west facing into the Twin Lakes drainage.
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Red Lady; Wet Slabs and Snowmobiles

CB Avalanche Center 2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 04/10/2020
Subject: Red Lady; Wet Slabs and Snowmobiles
Aspect: South East, South
Elevation: 12,000

Avalanches: D1 wet slab at the saddle between Coon and Wolverine. Looks like it failed late in the day yesterday. A few small pieces of the cornice triggered a loose wet that stepped down. Maybe warming around the rock band had water running along bed surface. Crown is 25-30 cm.

Weather: Intermittant clouds and sun with little to no wind. Temperature in the 30s, but felt like 50. T-shirt and no gloves at 9:30.

Snowpack: Solid overnight freeze despite mild temps. Surface warming quickly; especially the dirtier portions of the snow surface.

Photos:

Hot in Gothic

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 04/09/2020
Name: Eric Murrow
Subject: Hot in Gothic
Aspect: North, North East, East, South East, South, South West, West, North West

Avalanches: By 11am the east side of Gothic Mountain came alive and produced frequent loose wet avalanches from steep, rocky east-facing terrain near and below treeline. There was loose activity every few minutes for several hours. Most were D1 in volume but one D2 was able to accumulate mass on a below treeline slope that had yet to produce much loose activity this spring and pushed debris down a gully into an impressive pile at valley bottom, ran at 1pm. (see photo).

Weather: Very warm with clear skies until 3pm when clouds and virga started to push into the area. Winds were absent at valley bottoms.

Snowpack: Spent the day near valley bottom at 9500′. Crust were 4 or 5 inches thick in the moring and by 1pm they had broken down enough that boot penetration was basically to ground or as long as your legs would allow.

Around 315pm crossed several northeast and east-facing slopes, 9500′, and found that some slopes were unsportive to skis at times with minor collapsing of the barely intact crusts. More northerly slopes had intact slab structure where as east was just a broken down crust sitting on wet snow.

Photos:

The freeze is not deep!

CB Avalanche Center 2019-20 Observations

Location: Brush Creek Area
Date of Observation: 04/09/2020
Name: Steve Banks
Subject: The freeze is not deep!
Aspect: South East, South
Elevation: 9,000-12,000

Avalanches:Some older wet and dry slabs. Only recent looking activity came out of steep, rocky West facing, tho all we could see was the toe of a large debris pile.

Weather: Sunny, warm, barely a lick of wind.

Snowpack: 4-6” thick freeze was supportive all morning. Snow below was sometimes large grained and wet, sometimes large grained and dry. Lower elevation are pretty trap-door pretty quick with the sun and warm temps. Several collapses noted as it began to thaw.

WSC Natural Wet Slide 4/8

CB Avalanche Center 2019-20 Observations

Location: Crested Butte Area
Date of Observation: 04/09/2020
Name: Turner Petersen
Subject: WSC Natural Wet Slide 4/8
Aspect: West
Elevation: 10,000

Avalanches: From work, I spotted a natural wet slab Avalanche across the east river valley. This avalanche ran sometime yesterday afternoon. The slide slid to the ground, and maybe 200 feet. West aspect, 10,000 feet. Below treeline.

Weather: Hot, Sunny,

Snowpack: N/A

Photos:

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Avery Diamond Face

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 04/08/2020
Name: Sean Feese
Subject: Avery Diamond Face
Aspect: South West
Elevation: 10000-12600

Avalanches: Skier caught and carried, was able to ski free from moving avalanche to safety. Avalanche broke above skier on the west side of a roll in cold snow. Slid on the ground, then popped up on to the snow surface when it reached deeper snow. Avalanche did not gouge or step down. Avalanche was approximately 20 inches of snow on a smooth rock surface. The debris ran for about 600 feet. The avalanche occurred about halfway down the face at approximately 11800.

Weather: Sunny, Breezy

Snowpack: The snow had a good refreeze from the night before, even in the valley at 10,000ft. The diamond face struggled to warm with the SW breeze. A few hundred feet from the summit the snow had started to corn up. The corn continued until the valley, and was supportable until around 2 or 2:30.

Photos:

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Washington Gulch Look Around

CB Avalanche Center 2019-20 Observations

Location: Paradise Divide Area
Date of Observation: 04/08/2020
Name: Evan Ross
Subject: Washington Gulch Look Around
Elevation: 9,000-12,000

Avalanches: Plenty of cornices that have released above treeline. Some were old and some looked fresh or at least recent. I didn’t observe any new cornice falls that also triggered a deeper slab avalanche below. Plenty of loose wet avalanches at all elevations from today and past days. Most of the natural activity has been on east south and west. Saw some roller balls on a NTL NW aspect and plenty of shiny snow surfaces around the compass.

Weather: Blue bird and calm. High temps at Elkton hit around 50 degrees.

Snowpack: Started the late morning off checking in on an ENE aspect at 9,200ft near Crested Butte. HS was ~100cm. Last night’s freeze and surface crust was about 18cm thick. The wetting front had moved through the early march interfaces. While the old facets in the lower half of the snowpack were of course moist. CT results produced hard non-planar breaks in those facets. Once that crust broke down later in the day. A loose wet avalanche problem, that could gouge into the rest of the snowpack, would have been the primary avalanche problem.

Headed out Washington Gulch in the afternoon. Loose wet avalanches appeared to be the main avalanche problem. Foot pen was often around 30 cm’s into wet snow, but the snowpack was supportive. I found a couple of areas that I punched through the snowpack into wet snow at the ground. Where I found a punchy snowpack I didn’t observe any collapses.

Afternoon Wet Check

CB Avalanche Center 2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 04/07/2020
Name: Evan Ross
Subject: Afternoon Wet Check
Aspect: North East, South, West
Elevation: 9,200-12,000

Avalanches: A few more Cornices Falls observed and natural wet loose avalanches.

Weather: Another Beautiful day. Mostly Clear Sky and light winds at the elevations traveled.

Snowpack: Attempted to stay fairly close to the Kebler TH and low in elevations to check on the wet snow bits. The snowpack stayed supportable for the most part with spotty punching through the snowpack. The upper snowpack was wet, or it was wet to the ground on some southerly facing slopes, and a small loose wet avalanche problem developed around the compass. You would need a steep slope to get one of those loose wets moving. In the morning all of those aspects would have been crusty and this wasn’t the first time this upper snowpack had gotten wet. I didn’t observe any collapses in the snowpack.

Targeted a couple NE facing slopes to see how water was moving through the snowpack and to add more data into other recent data on those aspects. My hunt for something concerning didn’t materialize on slopes below 10,000ft. It doesn’t mean the problem isn’t out there, but I didn’t find it. The wetting front on all slopes near and above 35 degrees was in the upper 20cm’s of the snowpack. I found some ice lenses down to ~20cm, but the general wet snow was in the upper 10cm of the snowpack with some moist snow below, before eventually becoming mostly dry. No CT results on the upper 60cm of snowpack in those test pits.