Sluffing on Emmons

10webCBAC Observations

Date of Observation: 03/10/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Mount Emmons, various aspects near and below treeline.

Observed avalanche activity: Yes
Avalanches: Skier triggered a handful of small loose snow avalanches involving the new snow; the longest ran about 1000’ vert.
Weather: S1 to S2 throughout the day. Calm winds where we traveled.
Snowpack: The new snow was not bonding well to old surfaces (sun crusts, wind board, NSF). Storm totals ranged from about 8” or 9” NTL to 6” at valley floor by 4 pm. The snow was cohesionless and sluffing, no cracking or slabbing yet.

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amr beginning of storm obs

10webCBAC Observations

Date of Observation: 03/10/2023
Name: Mark Robbins

Zone: Northwest Mountains
Route Description: amr ziggins, big, east bowl

Observed avalanche activity: Yes
Avalanches: old debris at bottom of big chute under the steep roll on the right hand side. Also old debris at bottom of ziggins, I skied in the trees so didn’t identify where it had come from. Maybe from the right handrail of the ziggins gully?
No storm instabilities on the first two laps. On the last lap around 3:30 things seemed to be reaching a bit of a tipping point, the storm snow sluffing more actively with some clean fractures, tho no real propagation
Weather: warm and wet. 3-4 inches of heavy snow when I arrived at 1, another solid 3 inches on the sled 3 hours later. Calm throughout the amr tenure, some gusts on the ridge
Snowpack:

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Rockfall triggered avalanche?

10webCBAC Observations

Date of Observation: 03/07/2023
Name: Mark Robbind

Zone: Northwest Mountains
Route Description: Playground

Observed avalanche activity: Yes
Avalanches: See photo.

Weather: Air temp surprisingly cool, didn’t get uncomfortably warm

Snowpack: Unsupportive sun crust on southerlies in the morning. Dry snow with very manageable wind affect near and below tree line north-northeast

Photos:

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Green Lake Bowl Cornice Avalanche

CBACCBAC Observations

Date of Observation: 03/08/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Green Lake area. Below Mt Axtell

Observed avalanche activity: Yes
Avalanches: The Cornice above Green Lake Bowl on Mt Axtell released sometime between yesterday and 9am this morning. I’d assume someone would have seen it yesterday afternoon if it was there. The resulting avalanche was very large in size. The fish in Green Lake were sloshed, but not displaced. The snowpack below the cornice was mostly cleaned out to the ground. However notably there wasn’t a slab avalanche that propagated any wider than where the cornice fell. The cornice above this slope was massive previous to this avalanche.

Weather: Overcast and fairly warm temps. Light winds below 11,000ft.

Photos:

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Shallow snowpack obs in lower Brush Creek

CBACCBAC Observations

Date of Observation: 03/07/2023
Name: Eric Murrow

Zone: Southeast Mountains
Route Description: Lower Brush Creek

Observed avalanche activity: No
Avalanches: nothing new observed
Weather: Thin high clouds reduced throughout the day. Mild air temps above the freezing mark. Moderate SW winds with some strong gusts.
Snowpack: Traveled through below treeline slopes close to valley bottom with depths ranging from 70cm on south up to 120cm on northerly aspects. Southerly aspects have thick melt/freeze crusts at the surface that soften and lost support to skis but remained intact preventing Wet Loose avalanches concerns from developing. On south and southeast slopes melt water has yet to reach the ground (did not dig on southwest). I was surprised to get moderate propagating test results at two locations on northeast-facing terrain (see images). Early season facets at the base of the snowpack remain weak with just enough slab cohesion for propagation.

Photos:

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Cement Creek and Star Pass ob

CBACCBAC Observations

Date of Observation: 03/06/2023
Name: Ben Pritchett

Zone: Southeast Mountains
Route Description: Cement Creek to Crystal Creek through Upper Taylor River to Taylor Pass.

Observed avalanche activity: Yes
Avalanches: Only a few cornice collapses, some which trundles vehicles size blocks. In one area near Star Pass the cornice chunks cracked a tiny D1 slab immediately below, but it did not propagate beyond the cornice collapse area.
Weather: Nice day, Southwest winds increased in the afternoon just enough to move snow along ridges. Valley bottom temperatures reached around 40 degrees
Snowpack: The March 3-4 wind event ravaged this area, scouring and sublimating snow surfaces in the alpine. The winds drifted snow deep into the treeline, forming discontinuous pencil-hard slabs in below-treeline meadows and behind wind-breaks near treeline.
Height of snow in wind-sheltered near treeline locations generally ranged from 140 to 180cm. We measured snow in the alpine generally around 150 to 170cm, but well over 300cm in drifts, with bare ground on ridges after the wind event.
We saw inconsistent new wind-slab formation in start zones, with scoured textures below many cornices adjacent to pockets of pencil hard drifts (mostly wind-eroded old drifts). These drifts proved unreactive, with no cracking seen through 50+ miles of terrain covered. The drifts were too hard to impact with snowpack tests.
Below 11,000′, snow surfaces wetted on southerly-facing terrain. We experienced a couple very localized collapses (with no visible cracking) where water percolated down to the mid-February crusts. Water was pooled on top of the uppermost crusts, around 30cm below the snow surface.

Photos:

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Wind will it end?

CBACCBAC Observations

Date of Observation: 03/06/2023
Name: Eric Murrow

Zone: Northwest Mountains
Route Description: Washington Gulch to Baldy Mountain and lap on Coneys at the end of the day.

Observed avalanche activity: Yes
Avalanches: I observed a couple of older Wind Slab debris piles with blown-over crowns on southeast aspect in Baldy’s Rock Creek Bowl and a northwest pocket on Gothic Mountain. Fresh cornice-fall triggered slabs created large avalanches in Peeler Basin (different from the other reported slide) and north aspect of Schuylkill Peak into Baxter Basin.
Weather: Relentless SW winds around 30-40 mph in the alpine with gusts over 60 mph. Temps at low elevations out of the wind felt a bit above freezing and wet snow surfaces on sunny slopes.
Snowpack: We went hunting for recent hard slabs formed by the wind and did not encounter signs of instability on stiff, supportive-to-ski, drifts on northeast, east, and southeast aspects at different elevations. We ski-cut and skied several smaller slopes with obvious hard slabs up to 12″ thick without result. Recent Wind Slabs in this area appear to be stubborn or unreactive now. Minor drifting was observed throughout the day but did appear to produce any significant loading.

Photos:

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Cornice fall triggered deep slab in Redwell Basin

10webCBAC Observations

Date of Observation: 03/06/2023
Name: Ian Havlick

Zone: Northwest Mountains
Route Description: Redwell Basin

Observed avalanche activity: Yes
Avalanches: Cornice fall triggered deep slab in Redwell. Failed sometime after yesterday afternoon.

Photos:

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Hard slabville

CBACCBAC Observations

Date of Observation: 03/05/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Southeast shoulder of Gothic to 11,500′, and east side of Snograss BTL.

Observed avalanche activity: Yes
Avalanches: Several natural D1-1.5 wind slab avalanches on Axtell, Whetstone, and the Shield (Redwell Basin). One in Redwell Basin that looked large (D2) from a distance.
Weather: Mostly cloudy skies north of town, partly cloudy south of town. Light winds below treeline except for some periods of strong gusts/blowing snow in valley bottom. Blowing snow continued for most of the day off of the high peaks, and near treeline was somewhere between the two.
Snowpack: Snow surfaces remained soft and relatively unaffected by winds below treeline on Snodgrass. In sheltered terrain, the snow surface was denser and creamier compared to yesterday, with no new slab formation. As we moved into more wind exposed near treeline terrain, surfaces were heavily wind affected, varying from eroded to the last crust or loaded into hard thin slabs. Fresh wind slabs on small terrain features ranged from 3″ to 16″ thick. Some produced cracking, some produced collapses, and others gave no feedback to stomps or ski cuts. I didn’t ski cut the larger looking slabs in a proper windloaded start zone because I don’t like messing with hard slabs.

Photos:

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Irwin wind slabs

CBACCBAC Observations

Date of Observation: 03/05/2023
Name: Irwin Guides

Zone: Northwest Mountains
Route Description: Irwin Tenure

Observed avalanche activity: Yes
Avalanches: Candy’s SS-ASc-D1-I 8-10″ X 30′ X 200′ MFC E aspect NTL

Pre-E SS-AE-D1- I 8-10″ X 40′ X 150′ MFC E NTL

NC SS-ASc-D1-I. 6-8″ X 40′ X 150′ MFC SE NTL
Weather: From 2100-1100 the winds averaged in the mid 40’s from the SW with several gusts in the 60’s-70’s topping out at 87 last night.
Snowpack: A few wind slabs on E NTL reactive to ski cuts, some quality breaker wind board on W N/ATL, and some nice pow stashes in the safe places down low amongst the forest creatures.

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