Snodgrass BTL Level 1 Avalanche Course Obs

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 01/06/2018
Name: Ian Havlick

Subject: Snodgrass BTL Level 1 Avalanche Course Obs
Aspect: East, South East, South
Elevation: 9000-10000

Avalanches:

no avalanche observed

Weather: Overcast skies and flurries intensified to S1-2 snowfall by 1400. Calm conditions, warm temperatures. Total snow accumulation by 1645 was ~1-2″ of relatively dense, moist snow.
Snowpack: Lots of profiles dug, average HS was 40-50cm consisting largely of facets and large grained depth hoar. Found some isolated old wind board, but did not observe any significant cracking or collapsing. Lots of CT and ECT tests produced no propagation or concerning results. dead as a door nail.

Photos:

Poor Beaten Snowpack

CB Avalanche Center2017-18 Observations

Location: Paradise Divide Area. Mt Baldy
Date of Observation: 01/05/2018
Name: Evan Ross

Subject: Poor Beaten Snowpack
Aspect: North, North East, East
Elevation: 11,200-12,800

Avalanches:
Weather: Moderate westerly wind at upper elevation ridgelines. Partly cloudy with mostly high thin clouds.
Snowpack: The poor thing is so beat. The white looking mountains sure look nice from a distance, but up close their snow surfaces sure are variable and worked over by the weather. For this area, low danger travel advice fit perfect and we didn’t really find much of a concern as it relates to potential avalanches, from low angle to very steep slopes. South and southeast slopes have patchy snow coverage. Sunny easterly slopes had warm snow surfaces and small NSF. Shaded easterly slopes and northeasterly to north facing slopes were cold and weak. Again, snow surfaces on all aspects could also be eroded by the wind, or have wind board, or have variable crusts, or be soft form the sun, or protected form everything and soft. Couldn’t really paint a trend as its all just variable and all over the place.

Couldn’t find any Christmas slabs of much concern. A watchful eye is still warranted.

Photos:

This basin wraps from east to north facing slopes. The snowpack down low had the most intact, but still weak, Christmas Slabs. Moving through the terrain those Christmas Slabs were sitting on a variable old snow surface from shallow to rotten to wind-board. Higher in the terrain the snowpack generally thinned and became more weak.

Looking SSW on this ridge. Blown off high on the west side, while the easterly side had lots of variable snow surfaces and wasn’t necessarily “loaded”.

Slab no more

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 01/02/2018
Name: Ben Pritchett and Eric Murrow

Subject: Slab no more
Aspect: North, North East, East
Elevation: 9,400-11,100′

Avalanches:

Went to check out the three size 2 avalanches that ran in Snodgrass 1st, 2nd, and 3rd bowls during the Christmas cycle.

Weather: cool, clear, nothing to note other than good faceting conditions
Snowpack: Trap doors opening, slabs faceting, couldn’t get anything to budge or crack despite dozens of steep slopes tested.

Photos:

1st bowl debris

1st bowl debris

quick look at layering adjacent to 2nd bowl flank – no slab remains

Looking down 2nd bowl rider’s left flank

2nd bowl debris

no cracking or collapsing while testing adjacent slopes to last week’s natural avalanches

looking up 2nd bowl path. Debris surface had faceted to 4F- to F+ stiffness.

Shallow and Variable Snow on Coney’s

CBAC2017-18 Observations

Location: Coney’s
Date of Observation: 11/30/2017
Name: Tim Brown

Aspect: North East, East, South East
Elevation: 9,800-10,800′

 

Weather:

BKN Skies, NW Winds M-S, Air Temps ~35F

Snowpack:

Far skier’s left side of Coney’s 2nd Bowl:  Persistent Slab structure is still reactive in isolated pockets of the shallow and variable snow up to 40cm deep.  On the way up, venturing out of old tracks produced several significant collapses and cracks up to 10m away and 30cm deep.  The problematic snowpack areas are where stiffer (P-K hard) and more supportable, wind-loaded snow overlies large basal facets and depth hoar.  We did not observe any slab displacement on the low-angle terrain (<30 degrees) where we traveled.  Several steeper gullies appeared to have deeper wind-deposited snow, but we avoided the siren-call of these nasty terrain traps.

 

Collapsing and Cracking Where Wind Loaded

CB Avalanche Center2017-18 Observations

Location: Brush Creek Area
Date of Observation: 01/01/2018
Name: Evan Ross, Ben Pritchett

Subject:
Aspect: North East, East
Elevation: 10,300-12,000

Avalanches:

About 7 small natural avalanches that failed during the Christmas Storm on north to northeasterly aspects at near and below treeline elevations. Traveling on similar terrain today didn’t produce any new avalanches.

Weather: High thin clouds increased in the afternoon. Partly cloudy. Moderate westerly winds at ridgeline and calm in the valley.
Snowpack:

HS was between 40 to 60cm on average. The Christmas Slab continues to weaken and break down. On below treeline slopes, the only obvious signs of instability were slopes with some form of old wind loading or thin wind-board on the snow surface. Traveling on these specific terrain features would produce collapses and radiate cracks up to 80ft. HS didn’t necessarily increase much on these more loaded features but rather the Christmas Slab was thicker and had more strength. On slopes with slope angles in the mid 30’s, the snowpack would shift downhill slightly as it collapsed.

Slopes without and extra wind-board didn’t show any signs of instability. The Christmas Slab was weak.  Typically the top of the slab has faceted and become fist hard, with only about 5cm of stiffer (1F) snow at the 12/23 interface.

At the near treeline elevation band, the snowpack became much more wind affected and variable. Wind-loaded terrain continued to collapse and radiate cracks on mid to upper 30-degree terrain. Some portions of these wind loaded slopes had stiff pencil hard slabs that didn’t show signs of instability and appeared stubborn to triggering given the hard slabs.

Photos:

Small Crack after passing through this little wind-affected terrain feature

Supportive Faceted Snowpack

CB Avalanche Center2017-18 Observations

Location: Paradise Divide Area
Date of Observation: 01/01/2018
Name: H Bradford and S Griffin

Subject: Supportive Faceted Snowpack
Aspect: North East
Elevation: 10,200ft

Avalanches:

No observed avalanches.

Weather: BKN sky. Calm wind, no blowing snow. No precipitation.
Snowpack: Shallow snowpack up to 50-55cm. Very faceted yet supportive. Isolated collapsing up to 10-15m. Cracking down to 20cm failing on 3cm of 2-4mm facets.

Photos:

L1 Avalanche Course

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 01/01/2018
Name: Dave Bumgarner L1 Avalanche Course

Subject: L1 Avalanche Course
Aspect: North, North East, East
Elevation: 9,200-10,903

Avalanches:
Weather: Light-moderate winds from the SE. Broken sky. Air Temp 4C
Snowpack: Both groups dug pits N-NE aspect, 10,100′ elevation HS 80cm in one, CT11 SC 57cm down on a 2-3mm facet layer, ECT14 SP on the same layer. The soft slabs varied from Top: F+ – 4F

Other pit was 10,237′ elevation, HS 60-70cm, CT Moderate SP 25cm down on a 2-3mm facet layer, soft slab. The soft slabs varied Top: F+- 4F.

Snow surface Temp – 6c

Skiing was variable but we accomplished what we wanted in out observations and practicing up and down tracks while students took lead with guidance by instructors. We toured out the road then skinned up Coney’s. Did not see or feel signs of instability on our ski up or down but found some soft snow but mostly variable wind packed snow over previous ski tracks. One group skied main bowl and the nose of convex corner while other skied left flank of second bowl.

Photos:

More Cracks

CB Avalanche Center2017-18 Observations

Location: Paradise Divide Area
Date of Observation: 12/30/2017
Name: Syd D

Subject: More Cracks
Aspect: East
Elevation: 11800

Avalanches:

None observed

Weather: Breezy with scattered clouds.
Snowpack: Toured up Poverty Gulch to an easterly face at about 11800′. As we were skinning up the last of the climb, a large crack set off, it was about 100 ft long and produced a loud “cosmic” sound. Unfortunately, I did not get a chance to see how deep it propagated. We did not experience any other cracking, collapses, or any other avalanche obs during our tour. After a investigatory pit we found that the total snow-pack is about 115cm. I did a small column test that produced a sudden collapse with moderate taps below the sun/dust crust as well as a shovel sheer test that failed with moderate pressure just above the sun/dust crust.

Photos:

Lots of whumping on snodgrass

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 12/30/2017
Name: Alex Tiberio

Subject: Lots of whumping on snodgrass
Aspect: North East, East
Elevation: 9700

Avalanches:
Weather: Partly cloudy skies, windy and warm. 41F when we left.
Snowpack: Went to scope out Snodgrass this morning, once above the aspens at the base of “abbey lane” there was a lot of whumping and shooting cracks. We dug a pit and got ECTP4 on a small 35 degree slope. After that we decided to bail.

Photos:

Snodrass tour

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 12/30/2017
Name: Avy 1 course

Subject: Snodrass tour
Aspect: North East
Elevation: 9200- 9866

Avalanches:

We saw old slides on NE aspect of all three bowls (1st, 2nd, 3rd) of snodgrass around 10, 400 – 11,000

Weather: Sky: Broken
Air Temp: 4 c
Wind: Light
N0 precipitation
Snowpack: Snow surface; – 2c
20 CM down: – 4 c
Group dug Two snow pits:
NE aspect, incline 32, 9866 elevation
(2) CT1 SP on 27cm down on 2mm-3mm facet layer
ECT 3 SP on 27cm down on 2mm-3mm facet layer
Other pit:
NE aspect, incline 26, 9850 elevation
CT4 SC 23 cm down on 2mm-3mm facet layer
ECT 11 SC 23 cm down on 2mm-3mm facet layer
Both groups observed collapsing during their tour up. Also saw shooting cracks on the up track.

 

Photos: