Snow/Wx Obs before the next storm comes

Location: Paradise Divide Area
Date of Observation: 11/21/2018
Name: AR

Subject: Snow/Wx Obs before the next storm comes
Aspect: South West, West, North West
Elevation: 11,000′-12,800′

Avalanches:

On a SW aspect of our descent, we had one small point release from the edge of a turn. New snow slid on the uppermost crust layer, but did not propagate and ran only about 50 feet. This point moved very slow, but did illustrate the potential for the newer deposited snow to slide on the crust below it, especially on aspects that have received solar radiation. As new snow accumulates with the forecasted Thanksgiving storms, this weak layering structure will become more reactive, with more fresh snow on the crust, and potentially on the lower crust or facets deeper in the snowpack.

Weather: Clear, calm weather. Steady mild temps throughout the day 26-30F, no clouds, no wind.
Snowpack: Our party of two toured on a western facing slope from 11,000′ to a ridge at 12,800′. The snow depth was variable depending on the terrain, ranging from 10-20 cms in the wind scoured upper chute to 80-90 cms in the open bowl below. We found a generally weak snowpack structure with little to no slab in most locations, though a prominent crust was present mid-pack shortly after we gained elevation from the valley floor. Digging two snow pits between 12,000 and 12,500 we found multiple crust layers mid-pack. The structure of the bottom of the snowpack was weak faceted snow, topped by 2-3 crust layers dependent on the aspect, topped by fresh and freshly wind deposited snow. SW or WSW aspects that had more solar exposure prior to last week’s storm cycle had a stronger crust. W and WNW aspects had a less defined crust. In shovel shear tests the weakest layer appeared to be between the crusts and popped fairly clean on a large facet layer between the crusts. Though we found and isolated the weakest layers, this layer did not propagate in ECTs, and with the variable structure due to terrain features, we found no slab or concern of propagation.
The surface of the snow was very soft for skiing, with few pockets of wind-stiffened snow.

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Pre-storm snow surface look around

Location: Paradise Divide Area
Date of Observation: 11/21/2018
Name: Eric Murrow

Subject: Pre-storm snow surface look around
Aspect: North, North East, East, South East
Elevation: 9400′ – 11600′

Avalanches:

There were numerous old, dry loose avalanches from the past weekend on a steep northeast facing terrain feature. Very small in size.

Weather: Clear skies, mild air temps, and calm winds.
Snowpack: Ascended from Pittsburg up underneath the east side of Schuylkill Peak. While ascending below treeline snow surface on north and east aspects were dry and weak with remnants of patchy surface hoar laying flat. A pretty poor surface for an incoming storm to fall on. As we transitioned towards Southeast the snow surface transitioned to a wet surface. These Southeast and south slopes had a thin layer (3cm) of moist facets sitting on an old melt/freeze crust. Later in the afternoon while descending this snow was beginning to refreeze and will likely be a slick crust as the new storm comes in. None of these surfaces will likely bond well to the incoming storm.
As we ascended higher, up to 11600′, the snowpack remained weak and faceted on north and east aspects with no current slab structure. On southeast slopes near tree line the snow surface remained dry and weak. Only slopes that were very near due south had a melt/freeze crust at the surface at this elevation.

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Location: Paradise Divide Area
Date of Observation: 11/19/2018
Name: MR

Subject:
Aspect: North, North East, South, North West
Elevation: 10,600-12,700

Avalanches: None
Weather: beauty day. Strong afternoon winds out of the Northwest ish transporting snow off ridge lines.
Snowpack: 4-6 inches of new snow from Saturday night on top of mostly faceted snow down to the ground in most Northerly spots. Stubbornly breaker suncrust on one high southerly aspect that we had to navigate to get back on the aspects we wanted to ski.

On North facing terrain, above where the snowplug forms below Emerald Lake, at around 12,000 feet, we did find a pretty widespread old layer with new slightly wind-stiffened snow on top, with several avalanches at most r1-d1 that I would assume ran on sunday.

Steve Banks threatened to not heart my instagram posts if I didn’t submit an observation. This is the sort of strong-arming tactic the bullies at CBAC will use on you if you don’t submit your observations! Just, you know, fair warning.

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Variable, Weak, Sharks

Location: Paradise Divide Area
Date of Observation: 11/19/2018
Name: Evan Ross, Eric Murrow

Subject: Variable, Weak, Sharks
Aspect: North East, East
Elevation: 9,700-12,800

Avalanches:

Just some small loose snow avalanches in steep or wind-loaded terrain.

Weather: Light west northwest wind at ridgeline. Otherwise just a standard clear and cool Colorado day.
Snowpack: Variable, is that best word to start with when describing the current snowpack. Both snow surface and snowpack structure are variable.

For now, the snowpack structure is beaten and weak. On the northerly and easterly aspects, we traveled today, its hard to say where you could find some “persistent slab” structure. Generally, the snowpack is full of weak layers with crusts and facets, while the actual slabs are much harder to find. If you do find a small slab and set it in motion, that would be a small bummer, but the available loose weak-snow that could be entrained would add to your current bummer experience. This bummer of a time could become a bummer for the rest of your season if the whole mess pushed you into those lurking rocky sharks. That would be a total bummer.

The snow surface is also a mess. If you stay away from the wind effected snow surfaces then the skiing sure is nice for what it is. Otherwise, those snow surfaces are also weak or crusty and fit right into what you would expect for a standard  poor start for a continental snowpack. New snow amounts from last weekend range from 4cm’s up to 20-30cm’s on some wind-loaded terrain. Most of the wind pillows we found were old with a skiff a new snow on them and not an issue, but we did avoid one or two pillows that may have been thicker. If you did find a slab in the upper snowpack from last week’s new snow, the facets and crusts that it was likely sitting on would not instill confidence. Small loose snow avalanches in the new snow and some gouging into the older snow were also observed.

Photos:

Halloween Bowl Paradise Basin

Location: Paradise Divide Area
Date of Observation: 11/17/2018
Name: Andrew Pearson

Subject: Halloween Bowl Paradise Basin
Aspect: North, North West
Elevation: 11800

Avalanches:

There has been two avalanches in Halloween Bowl out Paradise divide this year. The one witnessed happened 11/17/2018. It was human triggered and broke off in an area filled with trigger points. It didn’t propagate far and did not go all the way to the basin floor. I would call it and R2 D1 slide. The slope angle at and around the crown was 35+ and strictly N aspect. I would imagine that it failed on the faceted weak layer based on the pit I dug, which was right next to the slide same aspect and slope angle.

Weather: Clear, Partly Cloudy. Temperatures stayed around and below freezing majority of the day. Winds in the bowl were light. No precipitation (valid through 3pm).
Snowpack: Snow depth varying depending on wind deposit, but consistently around 70-80 cm in the deeper areas, where the avalanche occurred. In the pit I dug at 55cm was a prominent weak layer with faceted snow. On top sat a more consolidated slab about 20-30 cm deep. Top slab was about four fingers whereas the next layer was fist and rotten. When doing a CT test, There was failure at 55cm at 15 making it a CTM.

Photos:

Natural on NE Aspect, Treasury

Location: Paradise Divide Area
Date of Observation: 11/11/2018
Name: Joey Carpenter

Subject: Natural on NE Aspect, Treasury
Aspect: North East
Elevation: 12000

Avalanches:

There was a natural avalanche on the NE aspect off the ridge running SE below the “football field” of Treasury. R2D2. Limited visibility did not allow us to get a photo but I approximated on attached map.

Weather: Temps remained in the teens throughout the day. Light to moderate winds were transporting snow along ridge tops. Skies were obscured most of the day with only intermittent periods of longer distance visibility.
Snowpack: Leeward areas contain pockets of stiffening slabs across N, NE & E facing terrain NTL & ATL. 1-1.5mm facets below the crust formed in early November. Facets beginning to form on top of crust as well, .5-1mm in size. Multiple hand shears produced inconsistent slab structure based on location. Areas that have received more wind loading show more cohesive slabs where less wind affected areas have minimal slab cohesion. Spx BTL is more uniform and rapidly weakening.

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Shallow windalab off SE ridge of baldy

Location: Paradise Divide Area
Date of Observation: 11/09/2018
Name: Lawson

Subject: Shallow windalab off SE ridge of baldy
Aspect: North, North East
Elevation: 12000

Avalanches:

Shallow windalab naturally released off ene facing ridge into rock Creek basin. Happened 11/9 early or 11/8

Weather: Clear, windy
Snowpack:

Photos:

Observed Avalanche

November 8, 2018

Last weekend (November 3, 4, 5) we saw periods of heavy snowfall and large early season accumulations throughout the valley. The higher peaks and more favored mountains near Paradise Divide, the Ruby Range and even in the Anthracites received up to a meter of new snow in more drifted terrain. This brought a cycle of natural avalanche activity, especially on North through North East slopes where previous faceted snow from October provided a weak support structure for the new snow. Avalanches were reported on Mt. Baldy, Richmond Mountain and in Redwell Basin. 
As the storm cleared on Monday and into Tuesday, significant winds continued to transport snow and likely contributed to another natural avalanche cycle earlier this week. The valley’s newest weather station on top of Cinnamon Mountain showed sustained winds in the 25-30 mph range and gusts reaching 50 mph from the North-East. These winds are great for moving snow onto leeward slopes and creating slab avalanches. 
The middle and end of the week brought colder temperatures with overnight lows even dipping below zero, tapering winds and sunny skies. This rather benign weather pattern looks to continue into next week except for a quick chance for some light snow showers Sunday night. This will easily lull backcountry travelers into a more complacent mindset and draw us toward bolder lines and more dangerous terrain. Wind and storm slabs are morphing into persistent slabs with stiffer snow overlaying shallowly buried facets and weaker snow. These conditions are most likely to persist in areas where our snowpack is a little more robust, and therefore the places that seem to want to be ridden. 
If you are heading into the backcountry this weekend you will likely seek out the deepest snow you can find. If the slope angle in these areas exceeds 30 degrees, bust out your shovel and your probe to see what lies below the surface. On the south facing or lower elevation slopes, you may find minimal basel facets and more stable snow. On shadier and higher slopes you will likely find well-developed facets (weaker snow) near the ground and a slab on top indicating more dangerous slopes. And after you do that, send us a note with what you find! You can drop your observations on our facebook page, by email at cbac@crestedbutteavalanchecenter.org or by clicking the observations button on our website, cbavalanchecenter.org
IMAGE DESCRIPTION: Outline of natural avalanche observed on Richmond Mountain earlier this week

Snow/Wx Obs

Location: Paradise Divide Area
Date of Observation: 11/06/2018
Name: Alex R

Subject: Snow/Wx Obs
Aspect: North, North East, East, North West
Elevation: 12,000′

Avalanches:

An avalanche that occurred on Sunday afternoon was still visible today. Located in “College Bowl” on Mt. Baldy, this small slab avalanche started in a rocky outcrop high in the bowl, and stepped down to the facets in the bottom of the snowpack near the top of the path. This avalanche ran roughly 500 feet, R1D1.5, and was still visible even after Sunday’s storm. This avalanche occurred while four separate groups were skiing in the zone. Poor communication between the separate groups was cause for concern, and although no one was caught in the avalanche, it crossed a skin track set less than an hour before the slide, as well as ski tracks from multiple groups.

Weather: Our party of three traveled to the top of Paradise Divide and toured on Northwest through North and East terrain. Strong and gusty winds from the Southwest for the duration of our tour. Partly sunny skies, and mild temps around 30F.
Snowpack: With strong winds generally from the southwest, we noticed substantial wind loading and cross loading on north/northeast ridges and peaks in the Paradise Divide Zone. Wind slabs were actively forming on many terrain features. The depth of new snow from Sunday’s storm ranged from 15-40 cm, with higher amounts deposited in wind loaded areas. Depth of the snowpack was 60-100 cm. Two hasty pits dug on northwest terrain revealed 30-40 cm of facets on the ground, a 2-4 cm crust (from sun/warm snow at the beginning of Sunday’s storm), and 15-40 cm storm snow and storm slab. Two compression tests showed CT13 and CT20, with the failure on the crust/storm slab interface. East facing slopes did to have a faceted structure at the bottom of the snowpack due to the lack of snow prior to Sunday’s storm. East slopes were beginning to be affected by solar radiation and the storm snow was warming. Our party stuck to low angle manageable terrain and found creamy turns on both aspects.

Photos:

Daisy Pass area snow and avi obs

Location: Paradise Divide Area
Date of Observation: 11/06/2018
Name: Eric Murrow

Subject: Daisy Pass area snow and avi obs
Aspect: North, North East, East
Elevation: 9200′ – 11600′

Avalanches:

Significant natural avalanche on NE – E aspect in the Martini Couloir off of Mt. Richmond, D2 in size. This slide likely failed sometime on Monday, 11/5, during towards end of snowfall and certainly during windloading event (see photo below). While driving home also noticed a fesh slide in Redwell Basin off of Mt. Emmons. This slide was difficult to view but appeared to be a D1-1.5. It failed on an East aspect sometime during the day on Tuesday 11/6.

Weather: Few clouds with gusty westerly winds. Alpine peaks had steady plumes of snow blowing towards easterly aspects. Most of this snow was being blasted into the atmosphere with minimal loading.
Snowpack: Snow depth across NTL terrain ranged from 20cm to 70cm in general. Terrain we travelled through was very open and “alpine” like even though still in the NTL elevation band. We ascended generally easterly terrain ( NE – E). In the NTL elevation band the snowpack consisted of basal facets ( 5-20cm thick) capped with a crust (1-4cm thick) then this old snow was topped with 10 – 100cm of new snow from the past week. Distribution of this past weeks snow was extremely variable in open terrain. Winds from the past few days blasted the new snow around. Found a few spots of slabby new snow, but mostly thin breaker windboards in open terrain. One location at 11,600 ENE aspect had a drifted area that was well over 100cm deep. We didn’t experience any collapsing or significant cracking (all cracking was limited to thin windboard surfaces). Views of surrounding alpine terrain gave the impression that alpine windloaded features where snowpack was deepest presented the possibility of triggering slab avalanches.

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