Location: Crested Butte Area
Date of Observation: 02/07/2018
Name: Ben Pritchett

Subject: Wind slabs

Avalanches:

Several wind slab avalanches observed:
Gothic Mtn, West Face. Natural D2 off SW aspect, 12,200′.
Purple Mtn, East Face. Natural D2 off SE aspect, 12,600′.
Mt. Baldy, East FAce. Skier triggered D1 off E aspect, 12,400′.

Weather: Blustery. Above freezing in the valley floors, just below freezing up high. Efficient transport late morning through early afternoon.

Photos:

efficient loading on Gothic’s Northwest Face.

Winds ripping through the Kebler corridor drifted snow on Mt. Axtell.

Small skier triggered slide on Mt. Baldy.

Purple Mtn. wind slab, small end of D2.

Gothic Mtn. West Face, D2.

Location: Crested Butte Area
Date of Observation: 02/07/2018
Name: Ian HAVLICK

Subject: Elk and Evans Basin
Aspect: North East, South East, South, South West, West
Elevation: 9000-12400

Avalanches:

Widespread storm slab crowns on anything steeper than 35º from yesterdays storm, east facing, near and below treeline. Did trigger 2 seperate persistent slab avalanches today, close proximity remote, from low angle ridgeline, with slides failing on steep ridgeline convexities. steep, unsupported east facing BTL and NTL. PS slabs released 15cm below new storm snow interface. Genuine windslabs were dense, but seemed to be gaining strength quickly atl. Biggest avalanche observed today looked to be 4th Bowl Mount Axtell, Natural, NE facing, ATL, looked like storm snow, but potentially PWL?

Weather: Clear skies, gusty west to northwest winds tapered mid afternoon. Intense solar all day, and became noticeable around 11am, especially in wind sheltered trees and southerly facing terrain. Temps stayed cold ATL, and light NW breeze continued on Scarp ridge as of 1500.
Snowpack: cold dry snow, 8-10″ from yesterdays storm in terrain travelled today. Steady and significant wind transport by westerly winds onto lee and crossloaded terrain. Lots of scouring in upper Evans Basin, and Redwell near and below Gunsight pass. Skiers Right of Gunsight looked to hold better snow. 4 large collapses while skiing within close proximity to 3 other skiers, south facing, BTL/NTL. Structure on southerlies is poor NTL, waiting for load. BTL southerlies, still very thin and cooked.

Photos:

Location: Paradise Divide Area
Date of Observation: 02/07/2018
Name: Evan Ross

Subject: Blue Bird and Mostly Wind Related Soft Slabs.
Aspect: East, South East, South, South West
Elevation: 9,600-11,800

Avalanches:

Looking around the range there was: A number off small loose dry avalanches on steep northeasterly and easterly terrain, mostly above 11,500ft. Noticed a few wet related loose snow avalanches on NTL elevation easterly to southeasterly aspects. Saw one natural soft slab avalanche on Red Lady Bowl not long after sunrise, small in size. Several small windslabs on southeasterly terrain below mineral point. One large soft slab avalanche below ridgeline on an easterly aspect near Angle Pass.

Skier triggered one wind slab at 10,600ft on an easterly aspect. Failure was within the new snow and not at the interface. 8″ to 12″ deep. About 300ft wide. WS-AS-R1-D1.5-S

Weather: Blue sky and sure nice to have some new snow. At 11,700 westerly winds were steady at moderate speeds. Drifting snow for sure, but surprisingly less then expected given the density of snow and a good majority of the snow already transported. Sun warmed some snow surfaces but cool temps and wind held the February sun’s strength back.
Snowpack: Personal tour not looking to deeply into things. Quiet snowpack on these aspects, no obvious sings to instability, mostly managing wind-loaded terrain. Didn’t get to aggressive on east, southerly were holding up well. Around a foot of new snow from the last storm in the area.

Photos:

Location: Paradise Divide Area
Date of Observation: 02/06/2018
Name: Mark Robbins

Subject:
Aspect: South East, South, South West, West
Elevation: 9,500-12,600

Avalanches:
Weather: snowing s1-s3 most of the morning. Strong northwest? winds all day with large snow plumes coming off of baldy and growing cornices, see photo.
Snowpack: New snow about 10 inches. Several small underfoot collapses on south facing skintrack 9,500-11,000. Wind drifting snow into leeward southeastern terrain near and above treeline. We skied southern through western aspects with no results save one very small pocket of storm snow on a convex roll, see photo. Also skied and skinned a few inconsequential southeastern wind loaded pockets, and while it felt slabby underfoot we got zero results.

Photos:

Location: Paradise Divide Area
Date of Observation: 02/06/2018
Name: Ben Pritchett, Eric Murrow, Kreston Rohrig

Subject: Hunting the wrong beast
Aspect: North, North East, East, South East, South
Elevation: 9,600′-11,600′

Avalanches:

SS – ASc – R1/D1.5 – O. Failed on 4mm DH on a slick old bed surface.
SS – ASu – R2/D2 – O. Same structure, propagated wider and ran 800′ vertical.

Weather: Showery most of the day, with a significant pulse of snow from 10am till early afternoon.  Storm total ~10″ snow, with .8″ SWE.
Snowpack: Went looking to see if the Jan 20th interface would reactivate under the weight of a new load. Turns out the Jan 20th interface wouldn’t be our concern.
Found radically different structures between slopes that had and had not avalanched. We dug in 2 slopes that had not avalanched, which gave us information that we misapplied the slopes below, which it turns out had avalanched previously and had much different structure.
First, went to look for 1/20 interface in a deep spot with light drifting near treeline. Northeast aspect, 11,200′. HS 240cm. ECTX, with slab fractures within in the new snow. No concern at the 1/20 interface, down 50cm.
Second, went to look for changes to 1/20 interface within 10 or 15′ of a skier triggered avalanche from last week. Northeast aspect, 11,100′. HS 140cm. ECTX, with slab fractures within the new snow. No concern at the 1/20 interface, down 50cm.
Third, dropped into a slope that we believed had not avalanched this season, expecting to trigger a shallow storm slab in the new snow. A little ways down the slope, at the first significant roll-over, one skier placed a hard cut and triggered D1.5 slide, about 50cm deep. The hitch was the total HS was only 80cm. This slope had slid before, leaving a dramatically different 1/20 interface, with much, much, much weaker snow. There was no visual indication that the slope had previously avalanched, and only a change in feel underfoot right at the point of the avalanche.  After the first skier moved to safe ground, a second skier came down near the first track and remotely triggered (15′ away) a much broader avalanche in steeper adjacent terrain. Same structure, the slope had slid previously. At that point, both skiers skinned back to the ridge, opting to avoid this unexpected change in conditions and revert to the great snow on the lower angles sunny slopes.
Big lesson learned – thinking we were digging and looking for one problem, we found another problem, that was far touchier and broader propagating than expected. We were trying to figure out and find the weak layer responsible for the avalanches triggered a week before, which had been described as “wickedly touchy.”  Our evidence in profiles very close to the prior avalanches didn’t match what we expected to find, nor the prior reports.  Turns out we were in a completely different snowpack, because they were several feet outside of previous avalanches.  When the evidence doesn’t match the report (of touchy conditions recently) consider the weirdness as a sign of uncertainty – proceed with caution.  Fortunately, our habits of skiing the less exposed lines payed dividents, though it was too close for comfort.
Bottom line – head’s up, the slopes that avalanched in the Holiday cycle, or the early January cycle have reloaded in the deeper snow zones around Paradise Divide, and they may react much differently than the adjacent terrain with an intact full-season’s snowpack.

Photos:

shooting cracks in the storm snow on an east aspect at treeline.

detail of the avalanche scene. Skier 1 triggered small slide and posted up at #1 mark. Skier 2 then remote triggered from #2 mark. Skier 3 remained on the ridge. Skiers 1 and 2 skinned back up and the group exited via the ridge.

Overview w/ down & up tracks, plus avalanche locations.

crown of a repeat performer, in this case the D1.5 triggered higher on the slope.

flank of a repeat performer, showing structure.

Looking down the first D1.5 slide triggered on the first cut. The second slide was triggered from the horizon line below, into steeper terrain down and right.

the larger, remote triggered slide, which propagated around 200′ across the slope and ran 800′ vertical to the exit bench.

the structure from the repeat performer paths. The 4mm Depth Hoar was exceptionally weak and old bed surface exceptionally slick and firm from repeated avalanches.

Watching the remote triggered slide in motion.

Location: Kebler Pass Area
Date of Observation: 02/06/2018
Name: Ian Havlick

Subject: Scarp Ridge Obs/Avalanches
Aspect: North East, South, South West, West
Elevation: 10,000-12,200ft

Avalanches:

Pretty widespread storm slab instabilities all elevations after 1300 today. 12-16″ deep, running as dry loose. More storm slabbiness,
unsupported slopes were easily triggered on approach. Propagation up to 10-40ft depending on terrain. No
persistent slab concerns yet. Wind effected snow and windslabs definitely present as well.

Weather: Gusty (moderate) west-SW winds across UUWW all day, minimal solar radiation, S1-2 but
some peak precip rates a bit higher. Temps at ridgetop 12 degrees, 20 at SP.
Snowpack: Moderate wind transport, snow heavy at times, definite storm slab, shooting cracks
within storm snow, snow broke as slabs, but ran as dry loose sluffing. Minimal debris. Wind slabs remained
pillow-like and very soft. Keep eye on settlement rates over next 24-36hr, as well as solar wet loose
potential, entraining significant amounts. Peered and stomped into Peeler and Legends. Triggered small windslab, hardly ran. Poor vis but couloir may have potentially ran already in storm snow. Very poor and scary crust-facet-crust combo on untravelled SW facing slope, 40º steepness, representative of bc snowpack terrain. Friable crusts capable of holding a load, but very weak 3mm facets below. ski cuts produce shooting cracks and avalanche still running as sluff.

Photos:

Location: Paradise Divide Area
Date of Observation: 02/04/2018
Name: Evan Ross

Subject: Mostly Weak Snowpack
Aspect: North East, East
Elevation: 9,000 to 11,300ft

Avalanches:
Weather: Partly cloudy sky in the morning became overcast. Moderate westerly wind gusts at ridgeline otherwise calm winds at lower elevations.
Snowpack: Quick and easy to assess snowpack structure just feeling around. The snowpack was weak and lacked any PS structure. Warm temps from the past week have helped settle the upper snowpack and keep the facet sluffing in check. Below 10,000ft a 1 to 3cm surface crust was fairly widespread. Above 10,000ft that crust was confined to easterly facing slopes. HS was mostly in the 60 to 80cm range.

Found one pocket at ridgeline with obvious PS structure. HS was 95cm. Mostly a 4f- decaying slab sitting on F depth hoar. ECTX. CTM SC on the DH. Moving 15ft across the slope and the PS structure disappeared. It also disappeared shortly below the ridge.

Photos:

NNE aspect, 11,300ft. HS 95. Mostly a 4F- decaying slab sitting on F depth hoar. ECTX. CTM SC on the DH.

Location: Crested Butte Area
Date of Observation: 02/03/2018
Name: Ben pritchett

Subject: Copper creek
Aspect: North, North East, East, South East, South, South West, West, North West
Elevation: 9,500-12,200’

Avalanches:

3x WL-N-R1D1.5–I on South aspects above treeline off the ridge between Copper Cr and Virginia Basin.

Weather: Blustery day. Scattered snow showers before to, gorgeous mid day, and developing greybird in PM. Blowing snow in the alpine all day.
Snowpack: Below 10,000’ on sunny slopes the snowpack got wet, even saturated and isothermal on some features. Very strong influence of free water on the sunny sides with small fresh loose wet avalanches, even above treeline. Crusty surfaces on anything kissed by the sun under 11,000, and sun crusts we’ll into the alpine on southeast to west aspects.
North winds over the last week raked the alpine, leaving northerly bowls stripped, often down to talus.
Found decent skiing in alpine northeast to east terrain, with no collapsing or cracking. An inch of new snow last night drifted into dramatic leopard skin and tiger stripe textures with radically different ski quality based on local drifting patterns. Slabs were faceting and thinning on their margins.

Photos:

Location: Crested Butte Area
Date of Observation: 01/31/2018
Name: ADB

Subject: January extremes 2017 and 2018
Aspect: South
Elevation: BTL

Avalanches:
Weather: 0 inches of new precipitation in past 24 hours.
broken skies.
light winds increasing to moderate winds between 9AM and 1PM.
Snowpack: Snow courses: Keystone (Red Lady Glades)-please don’t ski through our snow course. Crested Butte snow course by Magic Yurt. Keystone was established in 1960 and Crested Butte was established in 1951. Thanks. ADB
snow course Date average depth SWE Date average depth SWE
Inches inches Inches inches
Crested Butte 1/27/2017 62 15.8 1/31/2018 19 3.4
Keystone 1/27/2017 68 17.1 1/31/2018 16 2.8
SWE=liquid water in the snowpack if you melted the snow.

Photos:

Location: Kebler Pass Area
Date of Observation: 01/31/2018
Name: Tyler Tegtmeier and Cam Smith

Subject: Red Lady Bowl
Aspect: South East, South
Elevation: 9,100 to 12,400

Weather: Mix of sun and clouds with temps in the mid 30s at the TH and getting cooler at higher elevations. Wind out of the West with 50mph gust, especially ATL. Blowing snow at and above tree line.
Snowpack: Snow in the sun at lower elevations was warming quick and turning slushy/wet. Skin track was iced up in the trees where shade kept the snow cooler with a noticeable icy crust. Above tree line the wind was blowing snow and snow was severely wind affected on the south side face. Cornices noticed along summit ridge. Bowl was wind affected as well with crust noticeable throughout entire descent. It was either a nasty breakable crust or we both forgot how to ski.