No obvious signs of instability

CB Avalanche Center2016-17 Observations

Location: Crested Butte Area
Date of Observation: 02/18/2017
Name: Chris Pruden
Subject: No obvious signs of instability
Aspect: North East
Elevation: 9,500

Avalanches:
Weather: Warm, Calm, Mostly Sunny
Snowpack: Large glide cracks observed on a SSE aspect below the Gothic Road. Otherwise, no obvious signs of instability were observed. Our group dug to 130 cm down but was unable to identify any buried SH and nothing was reacting in a small column test. Moist Pow skiing down to the river if you stayed away from any hint of solar aspect.

Cement

CB Avalanche Center2016-17 Observations

Location: Cement Creek Area
Date of Observation: 02/18/2017
Name: ADB
Subject: Cement
Aspect: North, West, North West
Elevation: ATL, NTL, BTL

Avalanches: None. A few rollers on descent on W/NW aspect. Lot of debris in bottom of drainage from loose snow avalanches over the past week.
Weather: Scattered skies with light winds BTL ; and moderate winds ATL with snow being transported (swirling).
Snowpack: Up to 2 inches of new snow/24 hours with rain lower 900 feet of BTL . Aside from due north aspects, crusts below new snow surface.

SH unreactive

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 02/18/2017
Name: Tim Brown
Subject: SH unreactive
Aspect: North, North East
Elevation: 9,500-11,000

Avalanches: Saw several small dry loose avalanches that ran in the last week, but ski-cuts produced minimal sluffing on steep, shady slopes today.
Weather:
Snowpack: Except for 40cm of dry F to 4F hard facets at the surface, this is one of the deepest and stoutest mid-season snowpacks I’ve seen on Axtell. The mid-pack in this shady, wind-protected area is mostly 1F hard rounds, but there are two layers of buried surface hoar still preserved below hard snow.

Neither of these layers were reactive to snowpack tests where we looked today: ECTX x 2 and PST 90/100 (SF) on 40 degree NE-facing slope at 11,000′ with HS 280cm, PF 45cm and PS 20cm. Similar to Evan’s ob from yesterday, an informal deep tap ECT produced no results on either of these layers. It was difficult to keep the saw in the lower weak layer during PSTs as the SH seems to be lying down flat. The upper (Feb 10th) layer is composed of 3mm SH down 75cm and the lower one (Jan 19th) is composed of 7mm SH down 95cm. We easily detected the upper one in the pit wall and pried on blocks to find the lower one.

These layers may become more reactive when we get a significant load or a wetting front reaches them, but they’re getting pretty deep to human-trigger in areas where they’re buried this deep and protected by such a stiff slab. Except for 40cm of dry F to 4F hard facets at the surface, this is one of the deepest and stoutest mid-season snowpacks I’ve seen on Axtell. The mid-pack in this shady, wind-protected area is mostly 1F hard rounds, but there are two layers of buried surface hoar still preserved below hard snow.

Neither of these layers were reactive to snowpack tests where we looked today: ECTX x 2 and PST 90/100 (SF) on 40 degree NE-facing slope at 11,000′ with HS 280cm, PF 45cm and PS 20cm. Similar to Evan’s ob from yesterday, an informal deep tap ECT produced no results on either of these layers. It was difficult to keep the saw in the lower weak layer during PSTs as the SH seems to be lying down flat. The upper (Feb 10th) layer is composed of 3mm SH down 75cm and the lower one (Jan 19th) is composed of 7mm SH down 95cm. We easily detected the upper one in the pit wall and pried on blocks to find the lower one.

These layers may become more reactive when we get a significant load or a wetting front reaches them, but they’re getting pretty deep to human-trigger in areas where they’re buried this deep and protected by such a stiff slab.

Avalanche Level 1

CB Avalanche Center2016-17 Observations

Location: Crested Butte Area
Date of Observation: 02/18/2017
Name: JSJ
Subject: Avalanche Level 1
Aspect: North, North East
Elevation: 10,300

Avalanches:
Weather: Warm, Calm, Mostly Sunny.
Snowpack: A few cms new overnight at TH. Shaded slopes keeping dry surface snow. Open solar slopes turned moist by mid day. Thin 5cm Rain crust found down about 30cms. A thin well preserved graupel layer is found directly below this layer. No instability found on small column tests. 1-19 surface hoar layer found 1 M down. Very stubborn to get it to shear and not reactive to small column stability tests.

SH unreactive

CB Avalanche Center2016-17 Observations

Location: Crested Butte Area
Date of Observation: 02/18/2017
Name: Will Nunez
Subject:
Aspect: East
Elevation: 9,000-11,000

Avalanches:
Weather: Overcast skies in the morning – Broken clouds in the afternoon. Light to Moderate winds out of the S-SW. Strong solar greenhouse affect enough to induce skin glopping.
Snowpack: SNOWPACK/AVALANCHE OBS:
Valley floor to higher up on slope the averages HS was 220cm. 6” of new snow with a boot pen 10cm ski pen 6cm. A quick pit showed F 1F P HS220 on a 25*slope, 165cm up showed a MFcr layer that was preserving a graupel layer. Jan 19th Buried SH was seen but not reactive to ECTs or CTs, it was hard to even brake apart after the tests and show that Buried SH was rounding. Many D1-D2 avalanches where observed looking West towards Schuylkill Ridge and East towards Gothic Peak. The one in photo is hard to see, it ran on the new snow/ wind loaded storm slab with what looking like a meter crown. No other signs of instability were observed on the east side of Coney’s.

Pit-Wall

Surface hoar was present, but didn’t find it to be reactive

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 02/17/2017
Name: Evan Ross
Subject: Axtell
Aspect: North, North East
Elevation: 9,400-11,600

Avalanches:
Weather:
Snowpack: More of the same. Upper snowpack continues to decompose and facet as the most recent snow since 2/10 continues to break down. Small sluffs were the only observed avalanche problem.

At 11,600ft northerly facing slopes on the ridgeline and above the start zones, glanced at a previously excavated snow pit and saw a very obvious layer of surface hoar down about 35-40cm’s. Didn’t spend much time, but that was some of the most concerning structure I’ve seen in a long time. Hinting at what may be possible to encounter. Observed several old crowns in the terrain that are mostly filled back in now. Looked at one of these old crowns and surface hoar was the weak layer, again about 40 cm’s down. Targeted a 39 degree slope that didn’t have a crown. 2/8 SH was down about 50cm and 1/19 SH was down 100cm. Both of these were back to being difficult to observe without column tests, unlike the more obvious SH in the pit in low angled terrain above the start zones. ECTN on the 2/8 SH. Informal deep tap ECT for the deeper 1/19 SH had no result. A single CT produced no results. Multiple tracks in the terrain with some on features of concern produced no results. Below 10,800ft the snow surface was covered with large surfaces hoar on these northerly slopes.

Baxter Basin snow surface obs

CB Avalanche Center2016-17 Observations

Location: Paradise Divide Area
Date of Observation: 02/17/2017
Name: Zach Guy
Subject: Baxter Basin snow surface obs
Aspect: North, North East, East, South East, South, South West
Elevation: 9500-11900 ft

Avalanches: Skier triggered several dry loose avalanches on very steep, northerly facing terrain N/ATL. One of these sluffs pulled out a small wind slab, about 10″ thick. All were D1 in size. No other signs of instability. Plenty of older avalanches from the past week or so, dry loose, wet loose, storm slabs, etc, but nothing ran today that we saw. See photos.
Weather: A few bands of clouds passed over mid-day, but overcast skies didn’t start building until 3:30 p.m. Warm day. Southwest winds began picking up in the late afternoon, light to moderate. No precip.
Snowpack: Northerly aspects: the snow surface is .5 – 1 mm near surface facets at all elevations, capped by a thin wind skin above treeline, and textured by wind in some places.
Southerly aspects: Crusts softened mid-day but refroze into a thick melt-freeze crust, (5 cm or thicker), did not observe any facets above or below the crust where we traveled. The crust was mix of textured and slick. One slope holding a thin melt-freeze crust (E facing) had facets below the crust.

This was a wet loose avalanche that ran earlier this week off of an E aspect NTL, but appeared to gouge out a persistent slab on a NE aspect, about 10,000 ft.

The wet loose cycle was more impressive here. More widespread D1.5’s and D2’s as there was more storm snow to entrain in this area.  East, South, and West aspects.  

Skier triggered loose snow avalanche pulled out a small wind slab on a high elevation, northerly gulley. This slab appeared to be an isolated instability in the terrain that we traveled in.

Some old storm slabs that probably ran last weekend.

Glide cracks are appearing on a lot of slopes. Yikes.  Sluff management required on anything steeper than 40 degrees today.

Test results on SH

CB Avalanche Center2016-17 Observations

Location: Crested Butte Area
Date of Observation: 02/17/2017
Name: Andy Sovick
Subject: Test results on SH
Aspect: North East, East
Elevation: 11650 ft

Avalanches:
Weather:
Snowpack: On Mt. Axtell, we found two reactive surface hoar layers in the upper snowpack on a NE aspect NTL. Moderate compression test results clean shears on a layer of surface hoar 25 cm deep (CTM 15, Q1), and two taps later, another failure on another surface hoar layer a little deeper.  We moved to an east aspect and dug 3 CT, no surface hoar in any of those pits, and capped by a sun crust.

Surface Hoar

CB Avalanche Center2016-17 Observations

Location: Crested Butte Area
Date of Observation: 02/16/2017
Name:
Subject: Surface Hoar
Aspect: North
Elevation: NTL

Avalanches: Saw debris and paths of wet loose slides that had previously released from far skier’s left side of Redwell along the cliff bands
Weather: Light west winds, clear, very warm.
Snowpack: No signs of instability except for previous wet loose point releases, the 30cms on top from our most recent storm had surprisingly little funk to it and skied great.

We dug a pit at the top of wrong chute: Elevation 11,200ft, N/NW, 35 degree slope. Our compression test revealed CTH SP, 95cms down on a layer of 2-3mm surface hoar interlaced with 1mm rounds. We also had a result of ETCX.

While the buried SH wasn’t super reactive in our tests, it was definitely still present in the more sheltered northerly aspect NTL that we dug our pit in.

Decomposing slab

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 02/16/2017
Name: Eavn Ross
Subject: Decomposing slab
Aspect: North East, East
Elevation: Mainly 11,500-12,600

Avalanches:
Weather: Melanoma inducing weather. Calm wind.
Snowpack: Upper snowpack contenues to lose strength as the decomposing and near surface faceting processes continue. Less of a sluffing issue today due to more wind effect on the snow surface. Didn’t encounter any small wind slabs like yesterday, but suspect you could have found a small slab in the right terrain. Maybe terrain with more cross loaded features. No other signs to instability, felt like low danger travel advice. Old snow interface was down about 25-30cm. CTM RP on decomposing stellars on this interface. ECT Break.

Didn’t spend to much time on due easterly slopes. Though I was feeling like I wanted to get off them by 11am. Mostly as previous wind deposited slabs started to warm and get thick.