Location: Kebler Pass Area
Date of Observation: 12/18/2018
Name: Steve Banks & Zach Kinler

Subject: SE-S-SW-W NTL
Aspect: South East, South, South West, West
Elevation: 12,000

Avalanches:

No new avalanches observed, though several shallow soft wind slabs were noted, presumably from the little storm late last week.

Weather: Warm temps around -5 C all day. A thick cloud band passed by late morning, then mostly sunny until 3 pm when clouds built in again. Calm winds increased in the afternoon with gusts into the 20’s and a little moving snow.
Snowpack: We went looking for Persistent Slab structure today and had a harder time finding it on Southerly slopes. Where we did find it it was unreactive to our snowpack tests. Southeast and South facing slopes had a noticeable lack of weak snow at the ground, while Southwest to West slopes still showed this PS structure to some degree. Overall HS ranged from 110 to 70 cms with areas above treeline being in the 20 to 60 cm range.
Non of our snowpack tests produced a result.
Surface conditions are a mixed bag and will be interesting in the future. South slopes had multiple sunbursts in places, while SW had a crust on top and a softer crust just below. All these crusts had small facets above and below. 2mm Surface hoar and 1mm Surface Facets were noted on all aspects and elevations traveled, though the sun and light winds were taking a toll on them.

Photos:

• Indy-Basin-20181218.pdf

• Elk-Basin-2018-12-18.pdf

• Asia-Profile-2018-12-18.pdf

Location: Paradise Divide Area
Date of Observation: 12/18/2018
Name: Evan Ross

Subject: Crusty and Dusty? Crunchy Bread and Soggy Bread? Good and Bad? Hard and Soft?
Aspect:
Elevation: 10,800-12,800

Avalanches:
Weather: Partly cloudy early in the morning, then overcast through noon and bluebird in the afternoon. Light winds at ridgeline with some moderate gusts.
Snowpack: Little bit of everything out there. Don’t need to talk about the crusty south, so how about the snow on east and north. No signs to instability today, but still traveling with the threat of Persistent Slab structure in mind. Spend a good bit of time skiing around on an above treeline northeast to east to southeast facing bowl. The Northeast portion of the bowl was mostly all old avalanche debris with about 20cm of NSF on top of those debris. Felt like skinning in a sandbox. Moving across to east the snow surfaces were not as bad in regards to persistent gains, but still some small faceted grains on the surface. Crusts formed as the slope started having southerly tilt and I didn’t spend time looking at those crusts. HS 100-130 at 12,000ft in this area.

Traveled through a good hunk of BTL north. These were steep upper 30 to 40 degree slopes and just about everything had previously avalanched this winter. HS around 50cm, no slab and weak.

Photos:

Location: Paradise Divide Area
Date of Observation: 12/18/2018
Name: Eric Murrow

Subject: South and Southwest bowls near Paradise Divide
Aspect: South East, South, South West
Elevation: 10,800′ – 12,450′

Avalanches:

Nothing new, but got a photo of a slide that was reported from the east side of Cinnamon last Thursday, This slide likely failed, 12/13 from heavy winds transporting the few inches of fresh snow that fell last Wednesday night, 12/12. This slide propagated across the entire eastern side of the summit terrain feature of Cinnamon.

Weather: Partly cloudy skies turning to mostly cloudy skies by about noon. Light snow started to fall around 2pm, but not hard enough to produce accumulations. Winds were out of the west and picked up with light gusting up to 15mph during the afternoon.

Snowpack: Poked around in two alpine bowls on S and SW aspects.

First, the SW bowl was generally blown off with exposed rocks transitioning to 25 to 40 of weak faceted snow with no Persistent Slab structure Present-some of this area was capped with a soft, weak crust.  This shallow or rocky condition covered 3/5ths of the bowl. As we traversed further into the bowl, north winds from the past week were able to drift snow on to a portion of the bowl because of the western ridge that defines that bowl. This ridge created a drifted seam of snow that ran down the length of the bowl. This seam of snow was a stack of dense wind slabs (1F+ and P- hard) around 100cm deep. Did not observe PSa structure present even in this drifted area but did not dig in the deepest area immediately behind the ridge feature. However, at the surface in this drifted area was a thin,3 to 10cm, wind/suncrust and immediately below was a thin layer of faceted snow. This structure does not currently present much hazard but with future loading could produce a Persistent Slab set up.

On the south bowl, we again found large areas of reduced HS from wind stripping. Probing across and down much of the slope and one quick pit did not showed Persistent Slab structure. Snow surface here was a suncrust around 3cm thick that was supportive to skis on steep slopes. This surface crust was resting on several centimeters of weak faceted snow below. This structure does not present a current hazard but if loaded with a substantial slab in the future it certainly would.

Take away from looking at these south and southwest alpine bowls was that no Persistent Slab structure present with the possible exception of drifted areas from crossloading. If you avoided the drifted crossloaded areas then you would very likely avoid any Persistent Slab structure.

Photos:

Location: Paradise Divide Area
Date of Observation: 12/17/2018
Name:

Subject: Schuykill
Aspect: North East
Elevation: 11,400

Avalanches:

No signs of recent Avalanche activity .

Weather: Winds out of the West 5 MPH . Grey skies with light snow in afternoon.
Snowpack: 130 cm at the top . South facing slopes crusty . North facing surface hoar becoming more prevalent.

Photos:

Location: Kebler Pass Area
Date of Observation: 12/17/2018
Name: MR

Subject: sun crusts and wind slabs
Aspect: North, North East, South East, South
Elevation: 10,000-11,500

Avalanches:

no new avalanches observed

Weather: building to overcast throughout morning, warm, low winds
Snowpack: south aspect – variably breaker crust with some soft snow still lurking in the trees from 11,300 down to 11,000 or so, more stout supportive crust lower down in the open.

north aspect – HS in due north facing protected trees at 11,100 – 125cm. No signs of instability on and off the skin track and few signs of wind effect in the protected trees. Soft snow wind slab widely present in more open north facing terrain (gun barrels) through all elevations (11,400-10,700 or so?)

Photos:

Location: Kebler Pass Area
Date of Observation: 12/16/2018
Name: Irwin Cat Ski Obs

Subject: Irwin Cat Ski Obs
Aspect:
Elevation: 10,200′ to 12,000′

Avalanches:

A few dribblers out of Castle valley R and Thread. All well below D1 in size.

Weather: Clear with calm winds gusting to 8 out of the W-SW. Warm with a high of 44* @ 10,200 & 33* @
12,000′. Moderate Solar.
Snowpack: No cracking, collapsing, avalanches observed today. Hand shots continue to be
effective to ground on our terrain. The 11/22 interface in the UUWW and New world is pencil hard. Moist snow
on all but straight west facing terrain.

Photos:

Location: Crested Butte Area
Date of Observation: 12/16/2018
Name: Steve Banks

Subject: More Gothic Obs
Aspect: East, South East
Elevation: 11,000-9,600

Avalanches:

No new avalanches viewed.

Weather: Sunny, hot, not a cloud to be seen. High’s +4 C with almost no wind.
Snowpack: It’s a mixed bag out there. SE slope at 11,000 almost softened enough to not be breaker crust, but it was breaker crust. On this aspect there was wet to moist snow in the top 6 cms and a couple crust/facet interfaces in the top 12 cms. Solid 4F->1F midpack on top of a P+ 14cm MF crust at the ground (October facets that have been through MF). There was a thin layer of 1mm facets on top of this crust, as well as some lingering 3mm facets on the ground below it. ECTX though prying on the column popped a smooth shear on top of the MFC in the 1 mm facets. This could be interesting to watch. HS was 72.
On East facing aspect BTL we received 2 medium sized collapses while regrouping. Probing found widespread PS structure and HS averaging 70 cms, though minimal signs of instability. The snowpack is feeling beaten below treeline, but it is hard to ignore the structure and the continual whumphing.

Photos:

Location: Paradise Divide Area
Date of Observation: 12/16/2018
Name: Eric Murrow

Subject: Below and near treeline obs out Slate River Valley and buried SH
Aspect: North, North East, East
Elevation: 9,300′ – 11,300′

Avalanches:

One unreported slide was visible on an alpine subpeak of Peeler. Debris was buffed over in basin below but still just visible.

Weather: Beautiful day with calm winds and lots of sunshine. Air temp on northerly slope at 10,400′ -2c @1:30pm.

Snowpack: Started in valley bottom and made our way up to ridge top and performed 3 profiles along the way on N and NE slopes. This area has seen some traffic over the past few days, and we travelled/dug in the vicinity of other tracks. First off the snow surface in most places had Surface Hoar- it was largest at valley bottom and diminished in size as we climbed and disappeared shortly before gaining ridge top.
HS from valley bottom to ridge top ranged from about 70 to 100cm with drifted locations up to 125 in locations travelled – several ridge top start zones that have good drifting windward fetches presumably had much deeper HS but we did not enter these start zones. In general slab structure was still present throughout this terrain with cohesive slabs being the rule not the exception. Pungy thickets did have generally weak snow, but open slopes held to the rule of slabs. Old weak facets near the ground showed signs of rounding, but with minimal gain in hardness, in each test profile. The structure looked poor upon inspection and in hand hardness but generally failed to produce concerning stability test results.
Buried Surface Hoar(wedges) was found in each test profile location, 9500′, 10400′ and 11300′. Shovel Tilt Test made finding the layer fairly easy in the upper snowpack – it was buried down 8 to 11cm in test profiles. There is clearly no slab resting above it yet just a few inches of low-density snow but if this layer does get loaded at some point in nearish future it could cause problems on shaded aspect near and below treeline not to mention the Surface Hoar currently on the surface.

We travelled off the beaten path in a few locations probing into different spots to establish general HS heights, locations that already slid this year during Thanksgiving avi cycle were more around the 60cm range and did not have much of a slab.

See profiles below.

Photos:

Location: Crested Butte Area
Date of Observation: 12/16/2018
Name: Will Nunez

Subject: Snodgrass Steeps
Aspect: North, North East
Elevation: 9,000 10,000

Avalanches:

Ax Small facet slugging running on the P hard 2cm crust. No other instabilities where observed

Weather: Clear, Warm, Light to no wind
Snowpack: Sx HS 63in, large to small SH on shaded aspects, F to 4F mid pack w/ P hard 2cm crust to 3mm F facets to the ground. NE to N Evl 10,000 8,000f

Photos:

Location: Crested Butte Area
Date of Observation: 12/16/2018
Name: CBSP

Subject: Sock it to me ridge
Aspect: North
Elevation: 10475′

Avalanches:

AE-SS-R1-D1.5-O
10475′
N aspect
44 degree slope
35’wide X 400′

Weather:
Snowpack: Avg. HS 45cm variable snowpack mostly poor structure. Upper half of pack 2mm facets with 2-3mm facets at the ground.Isolated persistent slabs lingering in areas that did not run natural sometime during the T-day storm.

Photos: