Date of Observation: 02/14/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Afternoon tour in the Anthracites, poked around on a variety of aspects to 11,500′

Observed avalanche activity: Yes
Avalanches: Skier triggered a couple of thin soft slabs near wind drifted ridgelines, ~6″ thick, small in size. Also some shallow sluffing on very steep, below treeline terrain.
Weather: Moderate snowfall rates. Light winds where we traveled with evidence of stronger winds in other locations. Overcast skies.
Snowpack: Storm total was 6″ at Ohio Pass and up to 10″ at the top of AMR, low density, cohesionless snow. There was just enough wind drifting to add cohesion and form isolated soft slabs near ridgetop, still fist hard, but propagating 20 feet. I also produced localized cracking 2 to 4 feet under skis in drifted areas. Otherwise, the new snow sluffed underfoot on slopes steeper than about 38 or 40 degrees.

Date of Observation: 02/13/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: East Beckwith, traveled on SE to NE aspects to 11,600′

Observed avalanche activity: Yes
Avalanches: Skier triggered a small sluff that gouged into old snow on a very steep, rocky face with a shallow snowpack.
Weather: Clouds increased late morning from clear to overcast. Light snowfall began around 1 p.m. along with periods of snow transport from moderate south winds.
Snowpack: The snow surface is faceted on colder aspects: anything north of ESE. Like our January layer, the weak layer on our snow surface isn’t large and well-developed, but could cause storm instabilities to be more sensitive or persist a little while longer than normal. On due east and east-southeast aspects, there is a thin crust (.5 to 3 cm) above small-grained facets (.5-1 mm), with dry, small-grained facets above the crust (.5 mm). On anything north of due east, the crust is lacking, just small-grained facets (.5-.75mm). On southeast and south, the crust is thicker and I didn’t observe any facets above it. As we gained elevation, surfaces are more variable from wind effects and facets are less widespread, with more fragmented and rounded grains from previous wind damage. Snow surfaces are weakest near steep and rocky terrain where the snowpack is shallower.

Date of Observation: 02/12/2023
Name: Eric Murrow

Zone: Northwest Mountains
Route Description: Slate River TH to Purple Ridge skinner up to 11, 700 feet.

Observed avalanche activity: No
Avalanches: none observed.
Weather: Low-level clouds in the morning gave way to high, thin clouds in the afternoon. Mild air temps and light winds.
Snowpack: A skiff of new snow overnight along the Ruby Spine – 1cm or less than a 1/2 inch. I toured around looking at the current snow surface in preparation for the incoming snowy weather. Slopes on the north half of the compass in sheltered areas have very light faceting near the surface but are small in size and do not appear to be all that problematic for the incoming snow. The south half of the compass developed crusts. The surface on a steep south slope at 11,200 feet had around 4 inches of wet snow resting above an old melt/freeze crust. Crusts slowly thin as you transition to due east. Some near treeline slopes facing east had a dusting of new snow that remained dry resting above a thin, melt/freeze crust or windboard. Most sunny features I encountered warmed enough today to glue the dusting of new snow to the underlying crust.
I was able to stomp on a few older, wind drifts near and below treeline without any signs of instability or cracking.

Date of Observation: 02/12/2023
Name: Eric Murrow

Zone: Southeast Mountains
Route Description: Brush Creek TH to West Brush Creek via snomo. Tour around easterly terrain in the Union Chutes area.

Observed avalanche activity: No
Avalanches: none observed
Weather: Mild temperatures, light winds, with thin, high clouds limiting solar radiation during the warmest portion of the day.
Snowpack: Snow depth ranged from 140 to 160 cm (10,000 – 11,700 feet). In sheltered areas, the soft slab above the January facets faceted away for the most part. Deeper weak layers from December and November continue to present poor structure but did not produce notable test results. East facing-facing slopes near and below treeline developed a 1 cm melt/freeze crust from recent warm weather. The steepest northerly features produced minor dry sluffing in the upper snowpack while skiing.

Drifts from the northerly wind event left scattered hard slabs on the south half of the compass. The recipe for trouble appeared to be sunny slopes with a large northerly fetch to gather snow from…features without a large fetch did not look concerning.

Date of Observation: 02/10/2023
Name: Evan Ross and Zach Guy

Zone: Northwest Mountains
Route Description: Ruby Peak area, traveling on south to east aspects near and above treeline.

Observed avalanche activity: Yes
Avalanches: Skier and snowmobile triggered a handful of small wind slabs on drifted features near treeline. Crowns ranged from 4″ to 12″ thick. They were stiff enough to break above you (generally 4F, some pockets of 1F).

Weather: Light northerly winds with no transport. Warming temps, clear skies.

Snowpack: Surfaces near and above treeline are wind affected by the recent wind event. Wind slab formation is fairly easy to identify; most terrain is soft, rippled sastrugi posing no hazard, while concave terrain features and steep rollovers have stiffer, smoother pockets of drifted snow that were sensitive to ski and snowmobile cuts. Observed some rollerballs on sunny aspects, but were back at the trailhead mid-day before things warmed up too much.

Date of Observation: 02/09/2023
Name: Evan Ross

Zone: Southeast Mountains
Route Description: Hunter Creek. 10,000ft to 12,000ft.

Observed avalanche activity: Yes
Avalanches: In Upper Hunter Creek and Brush Creek. All three recent avalanches below have seen recent wind-loading and they all have massive fetches.

The first wind-loaded test slope I put a track on, produced a result that slightly displaced a small wind slab. This slab didn’t push over the stauchwall. The crown was 4 inches to 2 feet thick and failed on a non-persistent density chance.

The next test slope was slightly steeper and connected to a much bigger wind-loaded slope. South, 11,800ft. A wind slab released in the upper snowpack, before stepping down into a couple of different more deeply buried weak layers. The resulting avalanche was large in size. The crown height ranged from 1 foot to an estimated 4 or 5 feet. In the section of the crown I could access, the avalanche released on a thin layer of small facets that were atop what looked like an old wind-board. This was about 10cm below the only crust in the upper snowpack. In another area, this avalanche stepped down to the lower half of the snowpack before further gouging to the ground.

Got a closer look at the previously reported natural avalanche near the top of Hunter Creek. South, 12,000ft. This avalanche appeared to fail similarly to the avalanche described above. The upper crown failed between P-hard snow above K-hard snow. The knife-hard snow had dust blown in on it from the ridge. Like the avalanche above, there appeared to be a thin layer of small faceted grains at this interface. There was 80 to 90cm of snow below the bed surface in the upper crown. Lower down on the slope there were two areas where the avalanche stepped down to near the ground. The upper crown height ranged from 2 feet to around 5 feet.

East, 12,000ft near Timbered Hill. I couldn’t see this avalanche well. It looked like a wind slab that released in the upper snowpack. D1.5. However, it could have been a deeper crown that has been refilling in the last couple of days. I’d estimate it ran around a similar time as the other natural avalanche in upper Hunter Creek.

Weather: Partly Cloudy. Moderate to strong northerly winds at 12,000ft.

Snowpack: Nice soft snow surfaces at lower elevations. I didn’t spend time noting where surface crusts had formed on sunny lower-elevation slopes. At upper elevations, there are still a few places with nice soft snow surfaces, but the majority of the terrain had wind-boards and hard slabs.

Date of Observation: 02/08/2023
Name: Zach Kinler and Evan Ross

Zone: Southeast Mountains
Route Description: Cement Creek trailhead up the looker’s left ridge of Horse Basin to Cement Mountain.

Observed avalanche activity: Yes
Avalanches: Spotted 1 large persistent slab avalanche in the upper Hunter Creek drainage on a South aspect above treeline, likely running in the last 24 hours. This slope has a very large fetch and has been loading during our recent NW winds.
Weather: Overall a fairly cold day with intermittent clouds and sun. Winds were generally light but moderate gusts began around 1:00 pm.
Snowpack: No signs of instability underfoot from valley bottom to the ridgeline and on a few drifted slopes near treeline while skinning and stomping. Snowpack depths ranged from 70cm at the lowest elevations to 130 cm at 11,700. The slab below treeline is mostly faceted with just enough support to hold up the boots. Above 11,000′ the midpack has a bit of 1 finger slab with the upper 60cm faceted. The early season weak layer at the bottom of the snowpack is 4 fingers and rounding. A profile on a slightly drifted east aspect at 11,700′ produced no results twice and failed on the isolation of the column once. The latter result was a bit surprising, not something I would expect to find across the majority of the terrain.