Observations

Date of Observation: 12/30/2020
Name: Eric Murrow

 

Zone: Northwest Mountains
Location: Evans Basin steep easterly shots
Aspect: East, South East, South
Elevation: 9,500′ – 11,200′

 

Avalanches: A couple of avalances in steep southeast terrain in Red Lady glades – near treeline type features. Look like storm slabs running on the old crust. Likely failed very early AM of 29th.
One D2 at the very end of Moonscape Ridge by Evans basin – ENE-facing very drifted BTL feature
Weather: Ugly cold at valley bottom in the morning, but comfortable temps near and below treeline in the sun. No snow transport observed on nearby high terrain.
Snowpack: Solar radiation moistened the snow surface on SE, S, and SW slopes up to 11,200′. Made for interesting breaker-crust skiing at 3pm once it started to refreeze. Relentless collapsing on low-angled terrain on the ascent. Lots of collapses on flat ridgeline above steep east-facing slopes but very little cracking and no resulting avalanches, hmmmm. Skied down a short steep east-facing slope without result, but probing sure confirmed the suspect structure below. Dug a couple of test profiles checking on SE facing features to see if the crusts below the new slab is a potential Persistent Slab problem; slab seems not quite cohesive and heavy enough to cause an issue at locations traveled up to 11,200′, BUT a disconcerting double-crust setup exists below the slab. Recent storm snow was around 30 – 35cm thick but still Fist to Fist+ hard and bonding poorly to the crust below (see photo). On collapse ran 100+ feet and shot cracks across a tiny NE-facing slope down to the 12/10 interface; upon inspection Surface Hoar (~5 – 8mm) was found below the recent storm at the likely 12/22 interface. Easily ID this interface with shovel tilt’s tests.

Photos:

 

Date of Observation: 12/30/2020
Name: Alex Tiberio

 

Zone: Southeast Mountains
Location:
Aspect: North East
Elevation: 10,500

 

Avalanches: A couple fresh naturals ran today near the snodgrass gothic saddle sometime between 10 and 2 and saw another older slide below gothic road closer to the snodgrass trailhead
Weather:
Snowpack: Talkative. Large collapses if going off the ski track

 

Photos:

Date of Observation: 12/30/2020

 

Zone: Northwest Mountains
Location: Slate drainage
Aspect: East, South East
Elevation: ATL

 

Avalanches: A lot of natural avalanches, huge on purple and one on gothic.
Weather:
Snowpack: Shooting cracks and a couple large collapses while breaking trail.

 

Photos:

Date of Observation: 12/30/2020
Name: Sam L

 

Zone: Northwest Mountains
Location: Upper slate
Aspect: North, North East
Elevation:

 

Avalanches: Observed a new large natural in Baxter basin.
Weather: Cold and clear. Traveling uphill on southerly slopes was very warm but with little discernible change in snow surface.
Snowpack: Traveling up hill through north facing terrain produced several large and rumbling collapses with shooting cracks running hundreds of feet (see photo). Skiing southwest terrain we traveled through 12 to 15 inches of consolidating storm overlying a stout sun crust.

 

Photos:

Date of Observation: 12/30/2020
Name: Zach Guy

 

Zone: Northwest Mountains
Location: Scarp, Peeler, and Gothic
Aspect: North East, East
Elevation: ATL

 

Avalanches: See photos. Several slab avalanches D2, maybe up to D2.5 on E and NE aspects ATL that likely ran early yesterday.

 

Photos:

Date of Observation: 12/29/2020

 

Zone: Northwest Mountains
Location: Gunsight road
Aspect: North East
Elevation: 10,000

Avalanches: Intentionally triggered several road banks and small steeper rolls. All D1-1.5. Persistent slab problem was very reactive today. Poor vis limited obs in other areas.
Weather: Warmest in the morning with cold temps in the afternoon. Light snow and light winds throughout the day with maybe an additional inch or two of accumulation.
Snowpack: It’s broke. Multiple large booming collapses. Many shooting cracks. Surprisingly some steeper slopes around 35* cracked but did not slide. Snowpack was less reactive in areas that slide last week.

 

Photos:

Date of Observation: 12/29/2020
Name: Zach Guy

 

Zone: Northwest Mountains
Location: Slate River drainage
Aspect: North East, East
Elevation: 9,000 to 11,200 ft

Avalanches: Decent storm slab cycle last night from Happy to Climax to Schuylkill Ridge along with a few persistent slab avalanches
Happy Chutes: Lots of small slabs and sluffs, mostly D1. A D2 persistent slab
Climax: Debris through several of the chokes, looked like more shallow storm snow instabilities but light was flat, probably D1.5 to D2.
Schuylkill: Numerous storm slabs about a foot deep that ran near to the bench, D1.5 to D2. Two small persistent slabs on lower rollers that either ran last night or today. We remotely triggered two small persistent slabs on small terrain features, about 3 feet thick.
Wash Gulch: Plow triggered persistent slab, D2.
Weather: Light snowfall in the morning. Light winds. About an inch of accumulation. Overcast in the Upper Slate, broken skies near town.
Snowpack: Numerous large collapses in open slopes on low angled terrain and in small clearings in steeper trees. Storm snow is about 12″ to 15″ below treeline and 18″ near treeline, fist hard. Persistent slab structure is about 3 feet thick below treeline (Fist down to 4Finger). Cracking at or near the storm interface, especially as we gained elevation. We tested for “repeat persistent slab structure” in terrain that slid earlier this month. The structure was not reactive in pits, but there is still a lingering persistent weak layer near the ground, just denser and smaller with less of a slab than a pristine snowpack that hasn’t slid.

 

Photos:

Date of Observation: 12/28/2020
Name: Irwin Guides

 

Zone: Northwest Mountains
Location: Irwin Tenure

Avalanches: SS-ASc-D1.5-O 40cmx5mx100m Thorntons. Remaining persistent slab is notably more resistant to triggers than last week. This past weeks skiff of new snow sluffs easily off old bed surfaces. Anticipate repeat offenders.
Snowpack: Continued local collapsing in previously untrammeled areas.

 

Date of Observation: 12/27/2020
Name: Zach Kinler
Zone: Northwest Mountains
Location: Evans Basin

Aspect: East, South East, South

Elevation: 9300′-11,000′

Avalanches: No recent activity

Weather: Mostly sunny and pleasant on this afternoon tour. Winds were calm in sheltered areas. Highs remained below freezing.

Snowpack: The snowpack is still grumbling a bit, like a Stubborn old man sending back soup at the deli. There are a few steep slopes that have not avalanched and SOME of them produced collapses and cracking while others did not. The slopes that cracked did not run. Sensitivity has decreased however specific areas require thoughtful evaluation.

2-3″ new snow. Toured mainly on aspects from S through E. HS 60-70cm in sheltered terrain. Recent crusts from 12/22 and 12/26 have welded themselves into one thick crust 2-3 inches thick on steep south-facing slopes. Moving towards east, the crusts taper with faceting around the 12/22 MFcr. Small surface hoar capping facets was found at this interface once on due east.

 

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Date of Observation: 12/26/2020
Name: Eric Murrow

 

Zone: Northwest Mountains
Location: Slate River to Poverty Gulch
Aspect: East, South East, South, South West, West, North West
Elevation: 9000′ – 11600′

 

Avalanches: A grouping of small loose avalanches near treeline on southwest aspect – guessing wet from warm weather on Christmas
Persistent Slab on west aspect of Baldy – few days old, likely from wind event on Wednesday/Thursday timeframe
Weather: Pleasant above the inversion zone with calm winds below treeline and light winds near treeline – no blowing snow observed
Snowpack: Just a rec ski day with no signs of instability underfoot on steep southwest slopes, or lower-angled easterly slopes. Not many slopes in the alpine in this area looked like good skiing; lots of breaker-crust-looking conditions and wind erosion on others. In early afternoon steep southwesterly slope softened just enough to make for some decent turns.

Photos: