Observations

Date of Observation: 03/29/2023
Name: Eric Murrow

Zone: Northwest Mountains
Route Description: Evans Basin on Mount Emmons and Kebler Pass/Ohio Pass corridor.

Observed avalanche activity: Yes
Avalanches: A few small loose avalanches from warming today. Two loose avalanches triggered slabs on east aspects. One older avalanche likely failed during Monday’s storm that initially failed in storm snow and then stepped down two more feet; this avalanche snapped on small tree in the runout (D2.5).
Weather: Increasing clouds in the morning that were mostly cloudy in the afternoon. Temps reached close to 40 degrees below treeline. Light winds at low elevations, no snow transport was observed above treeline in the areas I traveled.
Snowpack: I took a look at the impact of yesterday’s and today’s warming on the snowpack on the south half of the compass. In general, I found crusts 1.5 – 3 cm thick (up to 1.25 inchs). I did not find liquid water draining into the snowpack much below the surface. Crusts on some steep sunny slopes might be supportive to skis tomorrow, but I suspect slightly breakable. I observed several snowbike tracks on steep sunny below treeline slopes that did not produce avalanche activity.

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6176

Date of Observation: 03/29/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Ruby Range, viewed from Mt. CB

Observed avalanche activity: Yes
Avalanches: A couple of large cornice falls (Owen and Scarp Ridge), a handful of small wet loose on S-E aspects A/NTL, and a hot wind slab. These are new since I put binos on the same terrain yesterday around 11 a.m.
Weather: Clouds increased mid-day. Above freezing temps.

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6175

Date of Observation: 03/29/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Perry Creek, viewed from Mt. CB

Observed avalanche activity: Yes
Avalanches: Destructive natural persistent slab, S-SE aspect above Perry Creek, ran to the ground shortly below start zone. Turner spotted this one fresh yesterday afternoon.

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6174

Date of Observation: 03/28/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Viewed from Hunter Hill and Carbonate Hill

Observed avalanche activity: Yes
Avalanches: Documenting avalanche activity from last week.

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6172

Date of Observation: 03/28/2023
Name: Zach Guy and Eric Murrow

Zone: Southeast Mountains
Route Description: Cement Creek, Hunter Hill, Star Pass, and Carbonate Hill. Various aspects to 13,000′

Observed avalanche activity: Yes
Avalanches: An impressively wide persistent slab avalanche across the E/NE side of Teo Ridge looks fresh in the past 48 hours, 2300′ wide on Google Earth. Snowmobile triggered a couple of 2′ wind slabs above treeline, one remotely, one with a slope cut, and there were a few recent natural wind slabs. Documenting older avalanches from the past week in a separate ob.
Weather: Clear to few clouds, below freezing temps in the alpine. Light winds with transport on a few terrain features.
Snowpack: Recent wind slab formation was localized to terrain features with large fetches for northwest winds; they were sensitive to slope cuts on the 3/24 crust, which looks lightly faceted. No signs of deeper instabilities under the sled today. A pit on an east aspect near treeline produced non-propagating failure on the 3/20 faceted crust under a 55cm soft slab. Snow surfaces stayed cool enough to keep wet loose activity at bay; the only wet loose activity I saw was in the steep, cliffy terrain around Mt. CB this afternoon.

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6171

Date of Observation: 03/28/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Viewed from Carbonate Hill and Slate River Road.

Observed avalanche activity: Yes
Avalanches: Large persistent slab (D2.5) on the SE side of Schuylkill Ridge ran this afternoon during the warmup. A handful of D1-D2 wind slabs in the Ruby Range that likely ran yesterday or overnight. A slab on East Beckwith (NE ATL) broke near the ground on a steep, shallow, rocky slope, sometime in the past 48 hours.

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6170

Date of Observation: 03/28/2023
Name: Irwin Guides

Zone: Northwest Mountains
Route Description: Viewed from Irwin Tenure

Observed avalanche activity: Yes
Avalanches: Several fresh wind slabs above treeline, new since yesterday afternoon. Likely ran overnight.

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6169

Date of Observation: 03/27/2023
Name: Jaime Odin

Zone: Southeast Mountains
Route Description: Ascended/descended the south east shoulder of anthracite mesa to 10,400 ft

Observed avalanche activity: No
Snowpack: 1-2 ft of weak new snow present throughout the tour, with a mostly supportable crust underneath, except for in sheltered terrain, especially in dense timber. Average ski penetration ~30cm boot penetration ~60cm. At 10,400 ft on an open SE aspect 10 degree slope the surface height was 240cm. Underneath the top 25cm of new snow was an easily breakable crust with ~60cm of weak, faceted snow beneath. Another crust was beneath the facets but I did not dig under this second crust which was ~80cm beneath the surface. Pulling on an isolated column with a shovel easily broke a slab of the new snow at the first crust/facet interface, instilling little confidence in the current snow structure.

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6168

Date of Observation: 03/27/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Upper Slate, Purple Palace area to 11,000′, traveling on easterly aspects.

Observed avalanche activity: Yes
Avalanches: Snowmobile cut an 18″ wind slab on Slate cut bank feature that catches efficient downvalley drifting. The slab failed on the 3/24 crust on a south aspect BTL.
Weather: Overcast, S-1 to S1 snowfall with an inch or two of accumulation today. Light northwest winds and light transport below treeline. Still coooold.
Snowpack: Dug several pits within a few hundred feet of each other on SE, E, and NE aspects below treeline. I got a mix of hard propagating and non-propagating results at the 3/20 interface. The east facing pit, which I dug just above an old crown, had the weakest looking structure and was the only pit that consistently produced unstable results. I did get one propagating result on northeast as well, but it was on an old graupel layer about 25 cm below the 3/15 crust, and the result was not repeatable.
No signs of instability while breaking trail.
There is about 10-12″ of dry recent storm snow above the 3/24 crust on southerlies in Upper Slate, and 4″ to 6″ above the crust closer to the trailhead. On easterlies, the snowpack has remained dry down to the 3/20 crust, 30″ deep. The upper foot or so is fist hard but dense enough that it isn’t dry sluffing.

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6167

Date of Observation: 03/27/2023
Name: Eric Murow

Zone: Southeast Mountains
Route Description: HWY 135 observations

Observed avalanche activity: Yes
Avalanches: Large avalanche ran in Red Lady Bowl – I would suspect it ran today while wind-loaded. Large natural avalanche on the easterly side of M-Face on Whestone. This avalanche appeared to break fairly deep with rocks exposed; this feature is unsupported from below.
Weather: I observed moderate wind-loading above treeline onto easterly aspects.
Snowpack:

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6166