Observations

Date of Observation: 12/18/2022
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Upper Slate to Paradise Divide and Cinnamon Mtn, traveling mostly on southerly aspects and ridgelines.

Observed avalanche activity: Yes
Avalanches: Nothing new in this area since my visit to Baldy two days ago, except for the Augusta slide reported by Kinler. New vantage of more crowns from last week’s winds and older.
Weather: Partly cloudy, light to moderate southwest winds, no snow transport.
Snowpack: Snow surfaces are faceted and weak below treeline, with thin sun crusts in the upper few inches on sunbaked slopes. Where recent drifting overlaps with these layers, I easily triggered shooting cracks and collapses up to 6″ deep. These were harmless in size and fairly isolated, but a good indicator of how the current surface will be a problem with future loading. Above treeline, the snow surface is heavily worked by winds, ranging from hard sastrugi to hard wind board to hard wind slab that produce no signs of instability. I did not experience any collapses or signs of instability on basal weak layers either.

Photos:

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Date of Observation: 12/18/2022
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Various Aspects, primarily between 10,800ft and 11,800ft.

Observed avalanche activity: No

Snowpack: Informal observation, just traveling through the terrain.

Gladed westerly facing slopes around 30 degrees produced several shooting cracks. Skis were punching through the slab on hard turns.

ESE-facing slopes gave no obvious signs of instability with snowmobiles jumping and bouncing around on low 30-degree terrain next to steeper slopes. Felt really easy to get sucked into more aggressive terrain given the lack of obvious signs of instability.

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Date of Observation: 12/18/2022
Name: Zach Kinler

Zone: Northwest Mountains
Route Description: Saddle between Augusta and Purple.

Observed avalanche activity: Yes
Avalanches: Fresh persistent slab off Augusta/Purple saddle. See photo.

Photos:

5763

Date of Observation: 12/17/2022
Name: Scott Toepfer

Zone: Northwest Mountains
Route Description: Yule Creek

Observed avalanche activity: Yes
Avalanches: N’ly aspect off the ‘Nipple’ south of Ant up Yule Creek. Big. Estimate crown was 15-20 feet, whole face below the summit cliff band pulled out to ground, wall to wall. We did not notice it yesterday, (and we were looking up that way a lot) or this morning, but we may not have noticed this morning while we trying to stay warm. I’m going to classify it as HSNR4D3G Not sure starting elevation or other dimensions but the crown was visible from a long ways away. I’d bet money it hit valley floor. Sorry, no fotos.

5762

Date of Observation: 12/17/2022
Name: Jack Fanselow

Zone: Southeast Mountains
Route Description: Nordic skiing on Mike’s Mile trail

Observed avalanche activity: Yes
Avalanches: A small, D1 avalanche slide in the 2nd Climax Chute.
Weather: Sunny, no wind, 10 degrees F.
Snowpack: Unstable snowpack, with a persistent slab problem on all West to East aspects at all elevations and a wind slap problem on most higher elevation SW to NE aspects.

5761

Date of Observation: 12/17/2022
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Snowmobiled out West Brush and skied on the southwest side of Teocalli up to 12,200′.

Observed avalanche activity: Yes
Avalanches: A handful of recent slab avalanches up to D2 in size on the eastern half of the compass. There’s been so much wind in this area that crowns are a bit harder to decipher (wind slab vs. persistent slab) and put an age on it. I’m only documenting the slides that look to have fairly recent debris; there were a few others that are either older or just blown in now.
Weather: Cold temps this morning, pleasant this afternoon in the sun. Calm winds.
Snowpack: We noted two collapses while snowmobiling in the flats at valley bottom, radiating about 30 to 50 feet. Slabs there are about 18″, soft and faceting. On southwest terrain, there were no persistent slab concerns: now from the past few weeks is shallow and faceting now (1-2mm), capped by various thin melt freeze or wind crusts in some areas, without any underlying old snow. There were a few cross-loaded gullies where we managed for recent shallow drifts (both hard and soft), but they were unreactive to our ski cuts in steep terrain. Winds did a number on the alpine in this area; some of the problematic terrain is heavily eroded now, other terrain saw loading. Surfaces N/ATL are all worked by the wind.

Photos:

5760

Date of Observation: 12/16/2022
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Anthracite Range, Schuylkill Ridge, Axtell. Submitted via text or morning bino tours.

Observed avalanche activity: Yes
Avalanches: See photos and details below. Failures sometime in the past few days.

Photos:

5759

The weekly snowpack summary is here. While some areas in the Northwest Mountains received more than a few inches of new snow, the main story this week was clear skies, cold temps, and consistent wind transport and pressing. Accompanying this wind loading were some impressive natural avalanches and a lingering wind slab problem as we move into the weekend.

Weekly Summary December 9-16-compressed

Date of Observation: 12/16/2022
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Viewed from Mt. Baldy

Observed avalanche activity: Yes
Avalanches: Adding more avalanches to the previous observation. Ruby, Afley, Peeler Peak, Treasury, and Gothic. The Gothic slide may have run today, the others ran sometime in the past 4 days.

Photos:

5758

Date of Observation: 12/16/2022
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Mt. Baldy, traveling primarily on south and southeast aspects to 12,400′

Observed avalanche activity: Yes
Avalanches: A handful of destructive persistent slabs ran in the past few days. Most notable includes a pair of very large hard slabs (D3) on Purple Ridge that ran over Purple Bench and reached the Slate River, ~2100 vertical, and several others in the ~D2-D3 range off or Ruby Peak, Peeler Peak, Schuylkill Peak, Bichmond, and Gothic. All fit the same distribution pattern as previous cycles. Today’s observed slides were all on W to N to E starting near or above treeline. Hard to say exactly which days they ran on, some crowns looked very fresh (24-36 hours), others were more drifted in and probably ran during the peak of the last storm (~12/13)
Weather: Cold, clear, light northerly winds this afternoon on Baldy. I could see notable transport in the Southeast Mountains this morning, especially near Whiterock.
Snowpack: Apart from one collapse in a relatively thin area (from wind erosion), we saw no signs of instability under foot. Test results on a windloaded SE facing slope near treeline produced propagating results (PST 47/137 END) under a 130 cm hard slab (up to pencil hard). The weak layer is showing substantial improvements compared to the start of the month; It was 4F+ and rounding. Still an ugly structure and now scary consequences, but on an improving trend.

Photos:

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