Soft and Quiet

Location: Crested Butte Area
Date of Observation: 01/27/2018
Name: Evan Ross

Subject: Soft and Quiet
Aspect: South East
Elevation: 9,400-12,390

Avalanches:
Weather: Didn’t take any official air temps, but it sure was a cold day. Clear sky started increasing in the afternoon. Mostly calm to light winds below 12,000ft ridgeline. Moderate westerly winds at ridgeline. Snow plumes on the high points around the range.
Snowpack: Quiet and not much going on as it relates to avalanche problems. About 3 to 6″ HST from the last storm. Evidence of drifting but didn’t encounter any windslab issues in this terrain. Didn’t encounter any worrisome persistent slab structure.

On a northeasterly aspect at 11,500ft. Kicked off one very small cornice chuck that sluffed down steep 40 degree terrain gouging into a weak snowpack and sluffing down hill. The sluff rode up higher in the snowpack on lower angled (mid 30 degree) portions of the slope.

Photos:

Remote trigger near Pittsburgh

Location: Crested Butte Area
Date of Observation: 01/25/2018
Name: Zachary Treisman

Subject: Remote trigger near Pittsburgh
Aspect: North West
Elevation: About 10,000

Avalanches:

R2 d2 approx 70′ wide crown about 2ft deep slid in a path I’ve heard called iron curtain on the lookers left side of the north facing bowl above Pittsburgh. Probably remote triggered by our party of four out in the flats a good 100 yards away from the slope. I’ve never seen a remote trigger that far away but we had a big whoomph and a couple seconds later the slope slid. Bare rock was visible in the start zone. Nobody was caught – everyone in the area was far enough from the bottom of the slope.



Weather: Partly sunny

Snowpack: Thin and sketchy

Photos:

Snow Safety team report

Location: Kebler Pass Area
Date of Observation: 01/24/2018
Name: Irwin Cat Operation

Subject: Snow Safety team report

Avalanches:

no new avalanche observations but did start to see rollerballs after 1500 on below
treeline, southerly steep terrain.

Weather: quite cold morning warmed by midday. high temperature at study plot 33. calm
conditions at all elevations.
Snowpack: Snowpack continues to settle, facet, and moisten below treeline late in the day.
Assessment in untravelled, alpine, west facing crossloaded gullies showed snowpack no deeper than 80cm,
consistently faceted 4F- hardness, and no significant layering. 3 handshots were unreactive.
Some rollerballs on steeper south and southwest facing terrain late in the day.

 

Middle Brush Creek, still shallow and collapsing

Location: Kebler Pass Area
Date of Observation: 01/24/2018
Name: Ben Pritchett

Subject: Middle Brush Creek, still shallow and collapsing
Aspect: North, South East, South, West, North West
Elevation: 9,000-12,300′

Avalanches:

Triggered one small D1 facet slough on a steep, rocky thin slope on a northwest aspect at 11,500′. Observed one recent D2 persistent slab avalanche on an east aspect at 10,800′ that failed to ground. See photos.

Weather: Gentle day, partly cloudy w/ high thin clouds. Cool temps and light westerly winds.

Snowpack: This was a trip into a radically weaker snowpack than what I’ve seen in the Western part of the CBAC forecast area lately. The overall snowpack seemed very similar to Paradise Divide in early December. HS averaged 40-50cm, entire weak. Snowmobiles trenched to ground w/ any throttle. Skis were barely supportive climbing, but it was easy to open the trap doors with any tip pressure skiing down. We experienced rampant collapsing and slope scale cracking in any open terrain on sleds or skis. No cracking observed in forested or rocky areas with a perforated/anchored snowpack.

Photos:

facet sloughing in steep northwesterly terrain

snow coverage in Cumberland Basin

a recent D2 persistent slab avalanche off Teo Ridge, east aspect, 10,800′.

one of dozens of shooting cracks crossing meadows

Baldy

Location: Kebler Pass Area
Date of Observation: 01/23/2018
Name: Steve Banks

Avalanches:

No new avalanches, but further evidence from this weekends cycle. Numerous D2’s mostly on NE aspects NTL. Not as many in the alpine, but maybe ran earlier and got filled in?

Weather: bluebird with strong solar. Temps stayed cold, around 20F as a high. Calm winds increased to mod gusts in the afternoon. Some plumes off the peaks.

Snowpack: 6-8” new snow over older 1F snow and 2” thick P hard suncrusts. Crusts were found on steeper solar aspects but not on anything less than 25 degrees. Sun was just beginning to affect some sheltered areas BTL. Intermittent Basel facets in shady sheltered areas.
Noticeable thin wind crust developing throughout the day with loading from the NW. Skin track got completely blown in from one lap to the next and noticeable wind whales forming on SE facing alpine slopes.

Cascade

Location: Kebler Pass Area
Date of Observation: 01/23/2018
Name: Ben Pritchett

Subject: Cascade
Aspect: East, South East, South
Elevation: 9,600′-11,400′

Avalanches:

One SS-N-R1-D1-O on a steep southeast bulge.

Weather: Cool clear day. Light Northwest winds produced light blowing snow above 12,000′.
Snowpack: Snow surfaces stayed dry on all but the sunniest steep solar collector type features. Creamy settled snow surfaces where the 1/20 snow remained in place. The wind had scoured some slopes back to the mid January sun crusts, but for the most part, surfaces remained soft.
Dug in an alpine’ish 11,000′ site on a steep due South aspect with an HS of 90 and found a very strong snowpack, with old percolation tubes between each of the 3 prominent buried crusts. The faceted “weak layers” between the crusts were at least 1-finger hard and sintering. This snowpack would hold a great deal of water before failing on due South.
However, transition just a little around the corner to southeast and the picture is less rosy. Southeast held much thinner crusts with weaker 4-finger facets between. This snowpack could fail at the 1/20 interface or even near the ground with 1-2″ of water respectively. It will be worth keeping in mind these crust face sandwiches on the southeast aspects when more snow arrives.
At the moment, there was no avalanche problem observed on these aspects. The wind lips (mini cornices) formed this past weekend were unreactive, with a strong bond at the 1/20 interface.

Photos:

Baxter Basin w/ plenty of evidence of recent drifting

Profile on a South aspect, 11,000′, strong snowpack at this site, but much weaker as you transition to Southeast.

only minor cracking and no collapsing showing good bonds at the 1/20 interface

~3 day old wind slab avalanche

Baxter/Cascade

Location: Paradise Divide Area
Date of Observation: 01/23/2018
Name: Ian Havlick

Subject: Baxter/Cascade
Aspect: East, South East, South, South West, West
Elevation: 9600-11700

Avalanches:

Observed a handful of suspiciously fresh avalanches, primarily on east facing, near and above treeline terrain, looked 10-20″ deep on steep slopes. One slide in particular looked very fresh near “Birthday bowl” (i believe) on Schuykill ridge–very popular run. Didnt see it on the way in, noticed late in day on return, no binoculars, so hard to verify age. D2 in size.

Weather: Mostly clear, a few wisps of clouds in the afternoon hanging around high peaks. Temperatures stayed chilly, even in afternoon. Highs in high teens, low 20s. Light breeze from WNW.

Snowpack: Snowpack traveled today was mix of setting powder from last storm, sastrugi, and stiff, dense wind stiffened snow from last 2 days of W-NW winds. Focused observations on southerly half of compass near and above treeline. Somewhat concerning snowpack structure with 2 significant layers to watch. One being the ~Jan 20th meltfreeze crust (and 1mm facets) which was buried by our last storm and windloading, and the second being the buried 2-3mm facets near the ground, both found consistently across southerly terrain. PST30/100end on 12/23 solstice facets on 38º, SE facing roll near treeline. ECTV on same layer, failing on isolation, 10cm off ground. Most suspect slopes on southern half of compass seem to be those steep, 35º+ slopes, which have seen significant (2ft+) windloading over the last few days, straining persistent weak layers. Observed one naturally failing steep drift on ascent.

Photos:

Snow Safety team report

Location: Kebler Pass Area
Date of Observation: 01/22/2018
Name: Irwin Cat Operation

Subject: Snow Safety team report
Avalanches: None aside from small windslab, SS-AE-R1-D0.5-I. (50cm x 100m x 40m) Peeled into the cornice and only ran 100′. Blocks and
debris nice and spread out on the slope

Weather: Clear, NW winds lightly transporting snow. Relatively cold with strong solar.
Snowpack: 20-30 cm’s of new snow only showing signs of cohesion or windslabs just below ridge
top. Aggressive ski cuts did not produce any results, mix of scoured and small pillowed windslabs behind trees, rocks, etc. Pasted with minimal ski pen 15cm’s. Evidence of wind effect down below treeline in open areas. New snow seems well bonded to 1/21 interface on SE (Sonic) with multiple hand shears pulling the top of the storm snow of but not at the interface.

Blustery, windy, snowy, coldy

Location: Kebler Pass Area
Date of Observation: 01/21/2018
Name: Evan Ross

Subject: Blustery, windy, snowy, coldy
Aspect: North, South
Elevation: 10,000-11,500

Avalanches:
Weather: Cold, windy, snowing, you get the point. Winds were moderate with stronger gusts in the Kebler corridor. Elevation didn’t really change the wind speeds, the wind speeds changes were more due to the openness of the terrain. At ridgeline winds were more north then northwest. HST was about 20-25cm at 11,000ft by 2:30pm. Less then reported elsewhere in the area. Probably do to windy weather.
Snowpack: Lots of snow drifting onto the Southern half of the compass in the Anthracites. Though this snow wasn’t failing on the 1/20 crust, nor was it enough load to collapse this crusts. This was one south facing slope at rideline in the Anthracites, higher in elevation or different terrain characteristics could certainly change things.

Got a couple laps in on some north facing slopes with no persistent slab issues or obvious signs to instability. Small, cross loaded windslabs were about it. Though these northerly observation are poor quality given the number of previous skier traffic in the terrain.

Small sluffing was the most widespread issue observed today.

Photos:

Anthracite Mesa N-NE

Location: Crested Butte Area
Date of Observation: 01/21/2018
Name: CB AIARE L2

Subject: Anthracite Mesa N-NE
Aspect: North, North East
Elevation: 9458′ – 10,800′

Avalanches:

Remnants of old avalanche on NE aspect near Avy one glades touring into Coneys’.

Weather: Group 1) 12:47 OVC skies, -11c Air, 10171′, Precip: S1, NNW Light-Moderate w/ Strong gusts occasionally,
Group 2)12:30 OVC skies, -5c Air, 10100′, Precip: S1, Moderate Winds
Snowpack: Group 1)10200′
HS: 100cm
HN:24cm
PWL @ 65 cm from surface on 2-3mm Depth Hoar: CT20 SC, CT15 SC, ECTP19 SC
Hardness of slab above PWL: F(srfc) – 1F
Below PWL: F to ground
Footpen: 50cm
Group 2) 10100′
HS: 95
HN: 24cm
PWL @ 80cm from surface on FC 1-2mm: PST 60/100 END
Hardness of slab above PWL: F(srfc)-1F
Below Pwl: 4F-P

Photos: