Snodgrass study pit

CB Avalanche Center 2020-21 Observations

Zone: Southeast Mountains

Location: E facing knoll on Snodgrass

Date of Observation: 11/26/2020

Name: Jack Caprio

Subject: Snodgrass

Aspect: East

Elevation: 10,000

Avalanches: None observed

Weather: Scattered clouds, sun coming in and out. Temps around 20’s. Light winds less than 10 mph out of the south.

Snowpack: I tested the snowpack on an east facing aspect below treeline. I found thin melt freeze crust at depths of 20 cm and 15 cm with F hard facets above and below. Sitting on the bottom of the pack are 15 cm of 1-1.5 mm facets

No exciting propagating results in stability tests. However, both the fractures on CT and ECT collapsed on the interface of old faceted snow and the melt freeze crust at 15cm. This weak layer crust has the potential to initiate, but it is unlikely to propagate.

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Weak layer smorgasbord

CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: Snodgrass

Date of Observation: 11/28/2020

Name: Zach Guy

Subject: Weak layer smorgasbord

Aspect: North, North East

Elevation: 9400′ – 11100′

Avalanches: Skier triggered several loose dry (facet sluffs) on steep, shaded aspects, D1 in size, entraining the upper half of the snowpack.
Investigated the reported skier triggered slab from yesterday. The slab was about 10 feet wide, 18″ thick, on a very steep, convex rock feature. It was a soft slab that appeared to fail on 1.5mm faceted grains on the ground. It entrained weak, faceted snow as it ran downhill. SS-ASc-R1-D1-O/G

Weather: Clear, calm winds, mild and inverted temps.

Snowpack: Widespread weak layer growth on all aspects and elevations! 2 to 4 mm surface hoar is developing on shady aspects up to about 10,000′, and pockety above that. Near-surface faceting in the recent snow is rampant on all aspects. The near surface facets are above a melt-freeze crust on SE-S-SW aspects. The entire snowpack is getting noticeably weaker in the past few days, becoming unsupportive and faceted throughout. We did not observe any signs of instability other than facet sluffing today. The current snowpack will become a problematic weak layer when/if we get a significant load.

 

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Slides on Snodgrass NE Lines

CB Avalanche Center 2020-21 Observations

Zone: Southeast Mountains
Location: 2nd Bowl
Date of Observation: 11/26/2020

Subject: Slides on Snodgrass NE Lines
Aspect: North East
Elevation: ~11k

Avalanches: D1.5, hard slab, 18 inch crown, interface between facets at the ground and newer 4F stiffness snow:

Dropping into 2nd bowl to check out coverage, stayed on the rail skier’s Right. Suspect terrain evaluated before skiing was exactly what slide: small convex rollovers formed over rock shelves in the top 50 feet of the line. Used a ski cut on top of one of these terrain features to get the entirety of the snowpack–which was about 18 inches–to fracture. Ran about 500 feet, picking up lots of speed and snow. The crown broke and propagated over pretty obviously terrain features, stopping at the concave gut of the line.

We made another ski cut just to clear the remaining hangfire and got a smaller slide to go, running only about 200 and entraining much less snow. D1.

Weather: Slight flurries, alternating sun and high cloud cover, 25-30F, no wind.

Snowpack: Ranging from a few inches on South faces to 2.5 feet on NE lines, from the ridge down to Gothic Road. F-4F slab sitting on about an inch of 2-3mm facets.

 

Reno Divide

CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: Cement Creek Road to Reno Divide area

Date of Observation: 11/26/2020

Name: Eric Murrow

Subject: Reno Divide

Aspect: North East, East, South East, South, South West, West

Elevation: 9,000 – 12,250′

Avalanches:

none observed. Visibility was not great but viewed several north and northeast alpine features without evidence of recent activity.

Weather: Low ceiling with clouds clipping the tops of peaks in the Elks that were greater than 13k. Winds were very light while traversing a 12,000′ ridgeline. Air temps felt cold in valley bottoms, but pleasant at 12k. I could feel the cold air still sitting in valley bottom on return trip home at 330pm. Clouds increased through noon with light intermittent snowfall and slowly decreased through 4 pm. No accumulations in this area.

Snowpack: Shady terrain near valley bottoms felt weak, although grain size was small, the faceting process appears to be happening in recent days.

In Reno Divide area, at 11,000′, new snow from two days ago was around 6 or 7 inches, with snow height in shady, protected areas around 55cm, a bit shy of 2 feet. Wind redistribution from the past few days was less than expected at 12k.  Closer to 13k and above looked wind effected with modest stripping of windward aspects. Traveled across a 12k ridgeline with mostly easterly terrain and struggled to find much recent Wind Slab formation, very isolated and generally soft at this elevation. Windward areas of this 12k ridge had soft snow still available for transport if the winds ramped up.

Northeast features above 11,600′ had dry 1-2mm facets at the ground like much of the CBAC forecast area. Stability tests did not inspire confidence with ECTP moderate scores, but stomping on and above small, drifty features produced no collapses or cracking.

Southerly slopes around 12k had thin, weak crusts at the surface with faceted grains below. Without any significant incoming storm on the horizon, this structure may change before it is tested by a new load.

Skied easterly terrain with about 50cm of snow that was reasonably supportive and provided nice turns.

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Fluff

CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: Coney’s

Date of Observation: 11/24/2020

Name: Zach Guy

 

Subject: Fluff

Aspect: East

Elevation: 9700 – 10,800′

Avalanches:

None observed: Good views of various aspects and all elevations.

Weather: Overcast clouds decreased to scattered. Light snow showers ended by mid-morning. Light winds. No snow transport observed on peaks.

Snowpack: About 6″ of incohesive new snow, evenly distributed across aspect and elevation. Some light wind affect in exposed areas from down-valley winds, where we observed some minor cracking in the new snow. The snowpack is right-side-up and showed no signs of instability.

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Gothic 7am Weather

CB Avalanche Center 2020-21 Observations

Zone: Southeast Mountains
Date of Observation: 11/24/2020
Name: billy barr

Subject: Gothic 7am Weather

Weather: Snow did not get going until nearly 10 p.m. but then was steady and moderate until about 5 a.m. when it stopped. Very mild overnight with light to moderate wind at times so snow is dense with 6½” new and water 0.56″. Snowpack is at the winters deepest at 14″ (it doe not get much deeper than this all winter, right?). Currently overcast and calm but not snowing with the temperature at the overnight low of 24F.

Gothic 7 a.m.

CB Avalanche Center 2020-21 Observations

Zone: Southeast Mountains

Location: Gothic

Date of Observation: 11/23/2020

Name: billy barr

 

Subject: Gothic 7 a.m.

Aspect:

Elevation:

Avalanches:

Weather: Cloudy, calm and warm overnight with very light snow, mostly between 10 p.m. and midnight but occasional flakes at timed. New snow ½” with just 0.02″ of water and the snow pack is at 7″. Currently overcast and calm and basically not snowing but an occasion flake comes at times. The overnight low is the current 26ºF. billy

Snowpack:

Gothic 7 a.m.

CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: Gothic

Date of Observation: 11/21/2020

Name: billy barr

 

Subject: Gothic 7 a.m.

Aspect:

Elevation:

Avalanches:

Weather:

Snowpack: Cloudy with snow starting after 1 a.m. holding generally light through the dark hours with 3″ new and water a dense 0.29″. No wind and snowpack is at 8″ deep. Currently light to moderate snow, obscured cloud cover, calm and temperature range after midnight 33F to the current 28F. billy

Cement Creek dirtmobile and skin tour

CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: Cement Creek Road to northeast side of Hunters Hill

Date of Observation: 11/19/2020

Name: Eric Murrow

Subject: Cement Creek dirtmobile and skin tour

Aspect: North, North East, East, South East, South, South West, West, North West

Elevation: 9,000′ – 12,000′

Weather: Mild air temps, mostly clear skiers, with light winds that slowly increased into the afternoon.

Snowpack: Traveled through a typically shallow part of the forecast area checking on snow cover, surface conditions, and to perform snowpack tests on drifted, shady terrain feature at upper elevations. Below treeline snow cover is shallow but pretty continuous across all aspects except for a good bit of dirt on due south slopes below 9,500′. Snow surfaces on sunny slopes near and below treeline were moist/wet at the surface and moist to the ground. Crusts have formed extensively on east through south through southwest slopes. Northerly slopes, even at lower elevations, remained dry and have started to facet in protected areas though the grains remain small, around 1mm. HS (snow depth) at the head of Cement Creek was only about 1 foot (30cm) at 11,400′.
Upper elevation northerly slopes were a mix of sastrugi and windboard. Traveled to around 12,000′ looking to find slab resting over weak snow near the ground. Walked across several stiff drifted pockets without signs of instability. Test site produced propagating results on a small drifted feature in old, weak 2mm facets at the ground (ECTP 11, see photo). The ground was very smooth at test site. Additionally, I had to probe this feature to find where the weak layer was present, it was discontinuous during probing and in a portion of my pit wall. Snow surface and slab were very stiff, supportive to boots. 20 feet to either side of my test site the slab tapered down to only 10 inches thick. Visually it was impossible to tell without probing. Nearby start zones immediately below ridgetop looked to have some small, pockets of slab present but they were not connected and very isolated across the terrain. Triggering an avalanche appeared unlikely but not impossible on upper elevation shaded slopes in this area due to the isolated nature of slab and weak layer.

 

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