Date of Observation: 01/25/2021
Zone: Northwest Mountains
Location: Schuylkill Ridge
Aspect: North East
Elevation: Near treeline
Avalanches: Skier triggered a large slide that “ripped to the ground…released way above me”. Skier was able to get out of the way of moving debris due to good radio communication from partners watching from a safe spot.
Photos:
Date of Observation: 01/25/2021
Name: Jack Caprio and Zach Guy
Zone: Northwest Mountains
Location: Ruby/Dyke area, then Anthracites
Aspect: North, North East, East, South East
Elevation: 10,000-11,500
Avalanches: We remotely or sympathetically triggered 6 D1 to D1.5 persistent slab avalanches on east facing terrain near and below treeline.
1 remotely triggered D1 on an east facing near treeline slope off Ruby Peak. This avalanche was triggered from about 200 vertical feet below. The crown was 18 inches of recent storm snow on facets ( 1/19 interface).
In the Anthracites, we continued to find instabilities. We remotely triggered one D1.5 soft slab avalanche which then sympathetically triggered 4 more small avalanches (D1 to D1.5) on the same terrain feature. All of these failed on facets just below the 1/19 interface with the crowns ranging from 24-30 inches of soft (F hard) storm snow. We also ski triggered a similar slide on a small rollover.
We observed a handful of natural soft slab avalanches that likely ran on Saturday, D1 to D1.5: 2 on east facing terrain below treeline, 2 on southeast facing terrain below treeline, and 1 on a southeast aspect near treeline.
Weather: Overcast skies with moderate snowfall all morning (S2) near Lake Irwin. We made our way over to the anthracites around 11:00 am where we were welcomed with broken skies and the occasional pulse of very light snowfall (S-1).
Snowpack: We generally found about 18-30 inches of recent F to F+ hard storm snow sitting on top of the 1/19 interface. This interface consisted of a thin, weak MF crust capping facets on southeast aspects and facets or facets below a thin wind crust on due east.
On east facing terrain below Ruby Peak, several collapses and an easily propagating extended column test (ECTP5) turned us away from some steeper and more consequentail terrain options. A couple of steps after the snowpit test, we remotely triggered a D1 soft slab from 200 vertical feet below the slope.
At the Anthracites, we took our first run on a north facing, below treeline slope. We did not observe any signs of instabilities aside from sluffing and a small pocket on a rollover. Stepping off the skin track near ridgeline, we observed several rumbling collapses on southeast, east, and flat slopes, along with shooting cracks. On our second run, traveled near some open, east facing terrain that had seen more wind loading, and produced a mess of avalanches from one remote trigger 50 feet from steep terrain
6 remotely/ sympathetically triggered persistent slab avalanches failing on the 1/19 interface continue to prove that this snowpack is setup for failure. In most snow-favored areas of our forecast zone, especially on leeward terrain features, we continue to find a grim persistent slab structure that is only in its infancy of causing problems.
Photos:
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Date of Observation: 01/24/2021
Name: Evan Ross
Zone: Northwest Mountains
Elevation: 9,500-12,000
Avalanches: 1 small storm slab from Saturday 1/24. North aspect at 10,000ft.
Weather: Overcast. Pulses of snow, ramping up the most in the afternoon. Picked up 3 to 4″ of new snow today.
Snowpack: Traveled through lots of terrain, but mostly lower angled slopes. Not much for red flags until we were riding slopes in the low 30-degree range on E, SW and W aspects between 11,000-12,000ft. Farther running shooting cracks in this terrain make it clear that we didn’t want to travel on anything big or much steeper. These slopes were upper BTL and NTL type terrain and didn’t have recent wind-loading.
Date of Observation: 01/24/2021
Name: Bo Torrey (Public)
Zone: Northwest Mountains
Location: Red Lady Glades 11,800′ Southeast Aspect (38.8694561, -106.9856561)
Aspect: South East
Elevation: 11800
Avalanches: R1, D1, storm slab. Natural slide – Not human triggered. Watched it go.
Weather:
Snowpack: Around 10 inches of new snow slide on a shallow snow pack
Photos:
Date of Observation: 01/24/2021
Name: Zach Guy
Zone: Northwest Mountains
Location: Slate River drainage
Aspect: North East, East
Elevation: 9,000 to 11,300′
Avalanches: We got a window of mediocre visibility of Peeler Peak and Scarp Ridge and didn’t see any noteworthy avalanches. Saw a pair of D1 storm snow avalanches on Schuylkill Ridge that ran yesterday; one was skier triggered, the other natural.
Weather: Very light snowfall (S-1) and calm winds all morning. Around 2 p.m., southwest winds increased to moderate and we observed a half-hour of heavy snowfall rates (S5). About an inch or two of accumulation all day.
Snowpack: 10″ to 12″ of settled storm snow over the well-described 1/19 interface. We observed a couple of collapses and got shooting cracks on three different slopes. Not a clear pattern to these: some were valley bottom, some mid track, and some near ridgetop. All of the signs of instability were on flat or shaded aspects where the 1/19 interface is weak, faceted snow (as opposed to a fair amount of windboard that also exists on the same aspects, or sun crusts on southerlies).
We tested a number of steep slopes with ski cuts and cornice drops with no avalanche results.
Photos:
Date of Observation: 01/23/2021
Zone: Northwest Mountains
Aspect: North, North East, South East, South
Elevation: 10500+
Avalanches: Natural soft slab R2 D1.5 on Cascade south. Looked to start in chute above tree line and run past summer road.
Weather: Gusty west wind and short lived inch an hour rate snow pulses in the morning. Small clearing from noon until 3 followed by light wind and snow.
Snowpack: Generally 40cm new snow on dry spell layer.
Date of Observation: 01/23/2021
Zone: Northwest Mountains
Location: Red Lady skin track
Aspect: East, South East, South
Elevation: 11,300
Avalanches: Intentionaly skier triggered this persistent slab R1.5 above some pretty steep and suspect terrain that no one really skies but is right off the skin track. Quite a stubborn release, but failed at or near the ground. Crown was approx 50 ft wide and well over a meter in places.
There were also three visible R1 storm slabs in the bowl. And one a bit below the aforementioned intentional trigger.
-KH
Weather: Wind gusts above TL easily pushing 45+mph.
Snowpack: Storm snow seemed to average about 30cm but some drifts up to 50cm near TL.
Photos:
Date of Observation: 01/23/2021
Name: Evan Ross
Zone: Northwest Mountains
Location: Upper Slate River
Aspect: North East, East
Elevation: 9,600-10,600
Avalanches: Didn’t observe any avalanche activity in the Upper Slate River. Couple nice periods of light, but otherwise flat light and hard to see. Getting back to town there were a few funny looking things in Red Lady Bowl. At least one small slab low in the bowl and a couple of others potentially on the looker’s left ridge. SE to E. Real bad light and hard to say.
Weather: Little flakes of joy kept falling from the sky. Isn’t that sweet? Sure made me happy!! We headed out at about 10am, fairly consistent S2 until about noon. Snowfall started to taper afternoon and by 1pm it was done with the sky becoming mostly cloudy. Winds were cranking up high with snow plumes throughout the day. Down low the winds were light to moderate.
Snowpack: Snow totals from last night and today were somewhere in the 10 to 14″ (25-35cm) range. While the 1/19 interface was now buried 40 to 50cm down. You were basically skiing in the weak layer, so conditions felt much deeper given all the soft snow on weak snow…
The recent storm snow was rather low density and didn’t have much cohesion yet. Though today’s winds were making the upper 10cm’s feel a bit top-heavy and gave a general thicker feel to the riding conditions. We primarily traveled on NE to E aspects. Down low, the 1/19 interface was well developed 1.5 to 2mm NSF that was very weak. Climbing above about 10,200 feet, and in a completely intact snowpack with no previous avalanche activity, the 1/19 interface was 1mm NSF and slightly harder at 4F-.
The bottom line, the 1/19 interface looks like a bad setup. We didn’t encounter any signs of instability while traveling on slopes in the lower 30-degree range. A few tests highlighted to the potential for storm slabs to break within the storm snow, but that didn’t really matter given the weak interface below that may become more of an issue as the new snow settles into a slab.
Saw lots of other ski tracks traveling on similar slope angles on different terrain features. Great to see folks out having fun and enjoying the new snow.
Date of Observation: 01/23/2021
Zone: Northwest Mountains
Location: Anthracites skin track near the top before your turn right to tree chit or left to 7th bowl
Aspect: North East
Elevation: 11,200
Avalanches: D1 propagated about 50 feet wide
Weather: Actively snowing and windy on the ridge. 20 degrees
Snowpack: Mid storm 15” new snow. 11am Saturday 1/23. Avalanche problem: storm slab
Photos:
Zone: Crested Butte Backcountry
Date: 1/22/2021
Name: Jared Berman
This week’s action consisted of several small snow events accompanied by heavy winds. Here’s the weekly summary showcasing how this event impacted our snowpack.
