Observations

Date of Observation: 02/12/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Schuylkill Peak area to 11,800’ on SE to NE aspects.

Observed avalanche activity: Yes
Avalanches: A small cornice fall in the past 24 hours. Minor skier triggered sluffs in extreme terrain.
Weather: Cloud cover decreased mid morning. Mild temps. Calm winds.
Snowpack: No signs of instability or evidence of avalanche problems. 1cm of low density snow fell last night without wind, which could facet or be a layer of concern with the next storm. Below that, surfaces are generally DF’s or wind packed rounds in wind affected terrain, some small grained faceting in wind sheltered northerly terrain, and melt freeze crusts on anything on the south half of the compass. Very steep and rocky terrain has weaker and more developed facets, occasionally unsupportive to boot or ski pen.

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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.

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Date of Observation: 02/11/2023

Zone: Southeast Mountains
Route Description: Snodgrass 2nd Bowl via skin track out of Tuttle Cabins

Observed avalanche activity: Yes
Avalanches: Small avalanche at the top of 2nd bowl
Weather: mostly sunny with increasing high clouds. Temperature estimate of 15F
Snowpack:

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The weekly snowpack summary is here.  A relatively quiet week highlighted by warming temperatures last weekend and a cold front with strong winds midweek.

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.

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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.

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Date of Observation: 02/08/2023
Name: Tad Barnes

Zone: Northwest Mountains
Route Description: Red Lady Bowl, Standard approach

Observed avalanche activity: Yes
Avalanches: D1- Redwell scarp ridge side
D1- Lookers right of Red Lady bowl gulley

Weather: OVC

Snowpack: Wind crusty in spots. 3 in wind slabs above treeline by skin track that were reactive to skier weight.

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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.

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Date of Observation: 02/07/2023
Name: Mark Robbins

Zone: Northwest Mountains
Route Description: anthracites

Observed avalanche activity: No
Weather: cold in the shade, hot in the sun. Calm winds
Snowpack: Enjoyed southerly skiing in the morning, sunday night’s storm snow had settled but not yet gone thermal on a crust that was supportive to skis but not to poles. By the afternoon the sun had done its thing to the new southerly snow. First skin glopping of the winter.

Evidence of the wind event really just at ridgelines, north facing snow from sunday night was as yet undisturbed and cold.

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Date of Observation: 02/07/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Daisy Pass to Hancock Peak to 12,400′, traveled mostly on NE and SW aspects.

Observed avalanche activity: Yes
Avalanches: A handful of small loose avalanches ran on steep southwest aspects as the snow surface got moist, and we triggered some small sluffs as well. Spotted one natural soft slab (D1) that ran from a drifted near treeline slope during the recent storm.
Weather: Clear skies, calm winds.
Snowpack: Went hunting for feedback on the wind slab problem and couldn’t really find any, apart from minor cracking below an alpine ridge. Evidence of wind effect and previous wind transport in the recent snow was less than expected. The strong pre-storm southwest winds late on Sunday formed wind crusts and wind board across most terrain before the snow fell, which appears to have effectively destroyed the faceted storm interface. Ski cuts on suspect terrain were unproductive. There’s about 5″ to 8″ of soft, settled powder on northerly aspects available for transport if northerly winds increase tomorrow.

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