Snow obs

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/17/2016
Name: Steve Banks
Subject: Snow obs
Aspect: East, South, West
Elevation: 11,900-10-500

Avalanches:
Weather:
Snowpack: East facing slopes in the morning had breaker crust but skiable. Quickly warming temps were hedged by increasing winds and clouds throughout the day. Slightly above freezing temps led to moist snow surface and softening crusts in the afternoon.
Found dry snow in protected WNW terrain sheltered by trees. No signs of instability on slopes up to 34 degrees. In the afternoon a refreeze zipper crust was forming on sunnier slopes

Wet avalanche

CB Avalanche Center2015-16 Observations

Location: Paradise Divide Area
Date of Observation: 02/17/2016
Name: Dustin e
Subject: Wet avalanche
Aspect: North East, East, South East, South, South West, West
Elevation: 9500-12500

Avalanches: R1-d2 natural wet slab on the southern side of purple ridge. Appeared as though wet loose debris from a rock band up high stepped down once it reached the weaker snowpack at lower elevation.  **CBAC note.  This slide is from a previous warmup. It was first observed the morning of 2/16**
Weather: Hot. Mild breeze up high kept things cool
Snowpack: Firm. New snow sat above v-day sun crusts and wind board. Did not punch through v-day interface all day, difficult to impossible to kick steps into this layer in many areas. Saw some cracking in new snow but slabs were 4″ or less and did not propagate far. New snow distribution above tree line is variable and as expected for nw winds.

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Ruby Range

CB Avalanche Center2015-16 Observations

Location: Paradise Divide Area
Date of Observation: 02/17/2016
Name: Zach Guy
Subject: Ruby Range
Aspect: North East, East, South East, South
Elevation: 9,400-12,500 ft

Avalanches: Some more rollerballs today on E and SE aspects A/NTL, and two very small wet loose on a SE aspect ATL, harmless in size. Had good views of a lot of the Ruby Range and no other fresh activity. Some older wet loose on below treeline southerlies from previous warm ups, one was a D2 in size and gouged to the ground (See Dustin’s photo).
Weather: Light to moderate SW winds with no snow transport. Clouds increased from clear to thin broken by PM. Warm temps
Snowpack: Near and above treeline, about 2-5″ of settled storm snow became moist to wet on E to S aspects, over the solid and still frozen VD crust. Surfaces refroze around 2 pm. as clouds and winds increased. Sloppier snow observed below treeline. No signs of instabilities on various aspects and steep terrain, except some minor rollerballs.

Small wet loose and rollerballs on a SE aspect ATL

Mountain Weather

CB Avalanche CenterWeather

Date: 02/17/2016

This morning, many valley locations look to be in the teens and single digits, while remote weather stations above 10,000ft hover in the 28-30ºF range at 0500. Today will be mild and clear, with increasing winds in the afternoon and throughout the night as a fast moving Pacific system barrels across the Great Basin and into western Colorado. This system is not looking to be a huge snow maker (3-6”), but winds look impressive at all elevations (50-80mph), and temperatures mild.

Snodgrass

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/16/2016
Name: Evan Ross
Subject: Snodgrass
Aspect: North East
Elevation: 9,400-11,100

Avalanches: Triggered a few very small facet sloughs in steep terrain that previously avalanched.
Weather: Patly cloudy due to high thin clouds. Calm winds during our tour, but we were either in protected areas or a to low elevations. Didn’t see any snow blowing off the peeks.
Snowpack: Ski pen in the 10-15 cm range with boot pen around 30cm. Many slopes have already avalanched and pose a very small facet slough problem if they are in the 40 degree range. Regarding the slopes that didn’t avalanche; some don’t have much structure at all, weak but still suportive. Others have obvious persistent slab structure, but it was unreactive. HS was around 100-130 on slopes that haven’t avalanched. Dug on one protected slope with an HS of 100cm. 1f decomposing slab over basel 4f, estimated 2mm facets. Slope test was 6 people kick turning on slope with no collapsing. The structure exists for some chance of an avalanche to happening, though we didn’t find the right place and didn’t observe any obvious signs to instability.

Snodgrass

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/16/2016
Name: Steve Banks
Subject: Snodgrass
Aspect: North East, East
Elevation: 9,400-11,100

Avalanches:
Weather: Partly cloudy and warm with moderate winds from the NW. Some plumes noted at higher elevations, but no evidence of wind transport NTL or BTL.
Snowpack: Was able to ski cut a fresh windslab on a small, steep convex roll on an obviously drifted and cross loaded feature around 10,000′ on a NE facing slope.
Quick snowpit in same area (but not cross loaded) showed 4 cm of new snow over rounding facets from 4f to 1f. ECTP 27+1 PC on the hardness change 37cms deep. Basel facets are large, but rounding and sintering.

Red Coon Glades

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 02/16/2016
Name: Alex Banas
Subject: Red Coon Glades
Aspect: South East, South, South West
Elevation: 9,000-11,500

Avalanches:
Weather: Few clouds, calm swirling winds near the top of RCG. Warm temps strong solar.
Snowpack: New snow has settled into a fast moving inch of warm snow. Stout 4-5cm MFcr provided mostly supportable skiing until 10,600′ from there on out the skiing was moist throughout the MFcr at 1300 hrs. No signs of instabilities throughout the tour. Moist grains 10cm below the MFcr @ 10,600′ dry below the crust @ 11,400′.

Snowpack obs

CB Avalanche Center2015-16 Observations

Location: Kebler Pass Area and Paradise Divide Area
Date of Observation: 02/16/2016
Name: Zach Guy
Subject: Snowpack obs
Aspect: North East, East, South East, South, South West
Elevation: 9,000-12,200 ft

Avalanches: Observed one fresh windslab on an east aspect of Scarp Ridge, ATL, small in size. See photo. SS-N-R1-D1-U. We dropped a cornice on a S facing windloaded slope above treeline and got a small 6-8″ wind slab to pull out, which ran on a mid storm layer but gouged down to the VD crust further downslope. SS-AC-R1-D1-S
Weather: Few clouds. Moderate NW to W ridgetop winds with light transport; some stronger gusts. Warm temps.
Snowpack: Settled storm snow totals are 3-4″ along Scarp Ridge and Peeler Peak, and 2″ on Schuykill Ridge, with drifts up to 12″ thick from NW loading patterns, mostly ATL and some isolated NTL features. Snow appears to be bonding much better today to the Valentine’s Day crust; minor cracking in drifts but otherwise it was hard to get the new snow to budge. Winds kept surfaces cool at upper elevations, but we observed some small rollerballing in windsheltered southerly facing cirques N/ATL. Below treeline the new snow melded nicely into older crusts. No natural wet loose observed and we traveled on numerous southerly facing steep slopes up to 40 degrees in the afternoon with no instabilities. The VD crust remained solidly frozen and supportive through most of the day; it began to thaw late PM near bushes and rocks on S/SW aspects NTL. The northerly facing below treeline slopes that we traveled were entirely weak and faceted out, with no persistent slab structure. No signs of instability with the PS problem on various aspects and elevations.

Fresh windslab on Scarp Ridge, E aspect ATL

Fresh windslab on Scarp Ridge, E aspect ATL

Gothic obs from 2/12-2/14

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 02/14/2016
Name: Geoff Unger & Chris Pruden
Subject: Gothic obs from 2/12-2/14
Aspect: All aspects
Elevation: 9400-11000

Avalanches:
Weather: High pressure with lots of solar on Friday. Cloud cover moved in midday Saturday and it snowed lightly on Sunday. Light increased to Moderate winds as the little disturbance arrived on Sunday.
Snowpack: On Friday 2/12 we toured in the road and did beacon drills. Of note was how slight changes in aspect changed the character of the snow dramatically. All but the most sheltered terrain has developed a crust. Just touring up the road it is easy to see the widespread natural activity that happened as a result of the 2/2 Storm event with slabs running up to D2-D2.5 over the past 10 days

Saturday 2/13 We toured up Copper Creek to get snow profile information. We dug on a WEST aspect and had mixed column test results. Even on a relatively sheltered West the crest had formed to make skiing less than desirable. Link to snow profile below.

Sunday 2/14 We toured up to the Snodgrass-Gothic Saddle. There was still good snow available for skiing on NE, but as soon as we trended E even the slightest bit the dreaded crust appeared.

Compression Tests revealed Buried Surface Hoar down approx. 39 cm on hard results on a NE aspect
CT 26 SP down 37 V 2-3mm / .5-1mm
CT 16 SC down 39 V 2-3mm / .5-1mm
It is possible the first result was also a collapse, but had the appearance of a planar fracture where the second result was a clear drop of the column.

 

 

Mountain Weather

CB Avalanche CenterWeather

Date: 02/16/2016

The quick moving storm that brought a thin new coat of new paint across our area mountains, will depart, leaving sunshine and clearing skies to dominate the next few days. However, those pesky northwest winds gusting in to the 30s and 40s above treeline with stick with us. Temperatures will rise near 40º today, and 45º tomorrow under a strengthening southwest flow aloft. Strong southwest winds and our first dust event of the season look likely on Wednesday night and Thursday with gusts into the 80s at the highest elevations.