Observations

Date of Observation: 03/18/2022
Name: Eric Murrow Ben Pritchett

Zone: Northwest Mountains
Route Description: Kebler Pass area. Mount Owen in the Ruby Range and Kebler Pass Road corridor.

Observed avalanche activity: Yes
Weather: A mix of sun and thin high and mid-level cloud cover. Temps slightly above freezing at valley bottom and below freezing temps on Mount Owen.
Snowpack: We traveled out to Mount Owen to inspect an avalanche that was reported to run at 11am on an east slope of Mount Owen. Investigating this slide it appeared that a group of snowmobilers/snowboarders likely triggered this avalanche remotely from low angled terrain around 600 feet away. It failed in the February facet layer; the slab ranged from around 50cm to 110cm thick (estimated as we did not measure across the entire crown face). The slab and the slope were shallower than expected based on snowfall totals this winter for the Irwin area. This avalanche was large in size (D2) and could have easily buried a person.

Late in the afternoon, an avalanche was reported to hit Kebler Pass Road. This avalanche was a Wet Slab that was likely remotely-triggered by a snowbike based on a nearby snowbike track. This avalanche failed in the February facets as well, and they were wet from meltwater when the crown was inspected.

Avalanches: In addition to the remotely triggered Persistent Slab on an east aspect above treeline on Mount Owen, the Wet Slab on an east aspect below treeline above Kebler Pass Road, we observed two fresh snowboarder-triggered slabs in the recent storm snow. Both were only a few inches thick and small in size.

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5496

Date of Observation: 03/17/2022
Name: Eric Murrow Ben Prichett

Zone: Northwest Mountains
Route Description: Cascade and Augusta Mountain area along the spine of the Ruby Range. Slate River corridor to Poverty Gulch and traveled on foot around the Angel Pass area.

Observed avalanche activity: Yes
Avalanches: Numerous loose avalanches in the storm snow around rocky areas near and above treeline. Several shallow slab avalanches in the storm snow were observed at upper elevations. All the fresh avalanche activity was small in size and generally not a threat to a person
Weather: New snow accumulations overnight ranged from 2 inches at valley bottom to 6 inches above treeline. Cloud cover alternated between overcast and broken. Light snowfall during the early afternoon hours.
Snowpack: In this snow-favored area, the snowpack was commonly near or deeper than 300cm. We dug several profiles on southeast, east, and north slopes assessing the Persistent Slab structure (see profiles). The profile from the northerly slope was in an abnormally shallow area as we looking for a “trigger point” type location where it would be more likely for the weight of a person to impact the weak layer. On the north half of the compass, the concerning February weak layer was generally 150+cm deep and 1 finger hard, no notable snowpack test results. No signs of instability were noted on the deeply buried weak layers.

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5495

Date of Observation: 03/17/2022
Name: Billy Barr

Zone: Southeast Mountains
Route Description: Gothic townsite

Observed avalanche activity: No
Weather: Cloudy, windy and mild with only very light, intermittent snow so just 1″ new and water 0.09″. Currently overcast with steady 5-10 mph W wind with the temperature 19F, also the days low. The snowpack is at 60½”, right around the average for this time of year. billy

5494

Date of Observation: 03/16/2022
Name: Eric Murrow

Zone: Southeast Mountains
Route Description: Lower Snodgrass above the East River.

Observed avalanche activity: No
Avalanches: Did not observe any new avalanches.
Weather: Increasing cloud cover throughout the day. Light winds with mild air temperatures.
Snowpack: I went looking for signs of instability in terrain where the Persistent Slab problem has a thin slab and a weak layer that is not improving (shady slopes with a relatively shallow snowpack). I was able to get a few small collapses and shooting cracks up to 20 feet on a slope with previous avalanche activity. This slope had reformed a slab 40cm thick (a bit more than a foot) resting over the February facet layer. Stability tests on this slope and an adjacent slope, that has not avalanche (slab around 70cm thick), produced propagating results under moderate force. Obvious signs of instability are decreasing, BUT stability tests and upper snowpack structure on shaded slopes suggest that human triggered avalanches remain possible. The snow surface on all aspects below around 9,800 feet became moist in the afternoon.

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5493

Date of Observation: 03/14/2022
Name: Zach Kinler and Ben Pritchett

Zone: Northwest Mountains
Route Description: Kebler Pass trailhead to Elk Creek

Observed avalanche activity: No
Avalanches: Site visit to document the recent rider-triggered avalanche, no new avalanches observed
Weather: Sunny and warm, finally felt like March. Calm winds below tree line and abundant sunshine with temps near to above freezing.
Snowpack: At the site of a recent large rider-triggered avalanche, the crown was 2-3 ft deep, it propagated around 150 ft wide and ran around 400 ft to the creek. A few inches of overnight snow are sitting on a thin melt-freeze crust from Saturday’s warming. It appears the avalanche failed on the 3/5 interface and stepped down to the Mid-February “sandbox” layer. The 3/5 interface is a soft melt-freeze crust with pit tests failing on small facets above the crust. A 50 cm soft slab(Fist to 4 Finger hard) is resting on this interface at this location. Failure occurred on this layer first, before the deeper, mid-February layer buried around 80 cm. While part of this slope likely avalanched early during the late February cycle, the slab/weak layer combo was obviously left mostly intact with the 3/5 interface forming during a dry spell before the last couple of storms.

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5492

Date of Observation: 03/14/2022
Name: Benjamin Schmatz

Zone: Southeast Mountains
Route Description: In the Gothic Townsite

Observed avalanche activity: No

Weather: 8/8 sunny warm

Snowpack: Reactive Layer found 55cm from the snow surface at the interface between the christmas storm and the long dry spell. No surprise there.
Melting precipitation particles near surface. Boot pen was 42 cm. Snowpack still mostly dry apart from some melt freeze crusts that have formed in February.

The proximity of the weak layer to the boot pen depth is concerning.

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5491

Date of Observation: 03/13/2022

Zone: Northwest Mountains
Route Description: NE Aspect @10,400ft

Observed avalanche activity: Yes
Avalanches: Human Triggered Slab Avalanche, NE Aspect, at 10,400ft, ran 400 vertical feet (estimated), 170-200 feet wide (estimated), crown 18-24 in (estimated)

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5489

Date of Observation: 03/13/2022

Zone: Southeast Mountains
Route Description: Mt. CB and Friends Hut area

Observed avalanche activity: Yes
Avalanches: A handful of recent avalanches submitted to CBAC via social media and CAIC database, coded below.

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5488

Date of Observation: 03/13/2022
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Snowmobiled on various aspects to the headwaters of Cement Creek, up to 12,000 ft.

Observed avalanche activity: Yes
Avalanches: More small wet loose activity today at all elevations, southern half of the compass. A few fresh cornice falls on Double Top to D1.5. A handful of small to large wind slabs that probably ran Friday above treeline. One deeper and fresher looking slab avalanche on a SE facing slope above treeline on Gothic Peak that ran sometime in the past few days.
Weather: Warm and sunny most of the day. Clouds quickly increased to overcast from 3 to 4 p.m. Moderate ridgetop winds this afternoon were starting to drift snow.
Snowpack: Still getting fairly consistent shooting cracks and remotely triggered mini slabs in creek beds below treeline on untrammeled shady aspects. Signs of instability diminished as I got higher in elevation, although I did get easy propagating results under a 2 foot slab on the Double Top Ridgeline (NE aspect, 11,600′). These instabilities are all on the sandbox layer, 18″ to 24″ deep, on average fist to fist+ hard and 2mm in size. Tried snowmobile cutting several hard wind slabs above treeline on small, supported features and the only result was me getting bucked off the sled.

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5487

Date of Observation: 03/12/2022
Name: Irwin Guides

Zone: Northwest Mountains
Route Description: Irwin Tenure: Upper Upper West Wall

Observed avalanche activity: Yes
Avalanches: These were largely unreactive to ski cuts but reactive to AE, most failing on the suncrust beneath this last storm cycle.
Field of Screams HS-AE-R1-D1.5-O FC (30cm x 30m x 200m)
Castle Valley Left HS-AB-R1-D1-O FC (70cm x 10m x 100m)
Castle Valley Right HS-ASc-R1-D1-O FC (20cm x 10m x 220m) ski cut at the top.

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5485