Date of Observation: 03/21/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Indy and Elk Basins. 9,000-12,000ft.

Observed avalanche activity: Yes
Avalanches: Many small storm slab avalanches at BTL and NTL elevations. Poor visibility ATL. Those avalanches failed last night or during the early AM hours. 40+ avalanches. All failing in 40+ degree terrain. There were fewer avalanches on due south-facing slopes and I didn’t see much for north-facing terrain. I didn’t notice any avalanche activity near the Kebler Road or on the lower northerly facing slopes of Mt Axtell.

Weather: Overcast. S-1. Calm wind.

Snowpack: HST averaged in the 25 to 35cm range. The storm slabs were failing just above the 3/20 crust in low-density storm snow and stellars. Hand pits still produced clean shears on the interface, but I otherwise didn’t observe any signs of instability on small test slopes. There was wind-affected snow at upper elevations, but I didn’t encounter any notable thick wind drifts and of course, also didn’t enter the most suspect terrain. On E-SE and W aspects The 3/20 crust was 2cm thick on average. There wasn’t enough load to start collapsing that crust into the weaker snow below. The crust on due south is thicker and stronger.

Date of Observation: 03/21/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Rec tour in the Anthracites, the usual stuff, avoided East Bowl.

Observed avalanche activity: Yes
Avalanches: Ski cut a storm slab in Ziggens. NE aspect BTL. The slab was 10″ thick and about 50′ wide, breaking on low density snow that fell earlier in the storm yesterday. Some small natural activity off the drifted feature on East Bowl.
Had some decent vis into the playground, Ruby Peak, Axtell, and Whetstone this morning and didn’t see any persistent slab activity.
Weather: S-1. Light ridgetop winds; signs of previous drifting near treeline.
Snowpack: 12″ of top heavy storm snow produced cracking up to 5′ long on test features, both on storm layers (northerly) and storm interface (southeast).
A quick pit on a wind-sheltered southeast aspect produced easy propagating results (ECTPV, ECTP9) in facets below the 3/20 crust. The crust was about 2-3cm thick, strong enough that I didn’t get any collapses on it while walking around on a few similar slopes. No results on the 3/10 crust here, and like elsewhere, the weak layer was not obvious. Probed around on a few NE facing slopes to verify the absence of the 3/10 crust…nothing on NE or ENE here.

Date of Observation: 03/21/2023
Name: Travis Guy

Zone: Southeast Mountains
Route Description: View from Gothic Research Meadow

Observed avalanche activity: Yes
Avalanches: Natural avalanche on Bellview

Weather: Cold, high clouds, -14C in Gothic. Calm.

Date of Observation: 03/20/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Skykill Ridge, Near OBJ. 9,000ft to 11,300ft. NE-E-S

Observed avalanche activity: No

Weather: S-1 most of the afternoon. Starting to pick up in the later afternoon as we were headed out. Calm wind.

Snowpack: Great skiing on NE with some sluffing in steep terrain. The crusts at the old snow interface on East were breakable and not good skiing. Not enough snow yet, for any storm slab problems. The most notable weak layer was the 3/20 interface that was buried this morning. On E and SE it was about 2cm thick, collapsible into weak snow below, and ready to aid in propagation once there is enough load. On south, that crust was 6cm + thick and strong.

Targeted a test pit on a ENE slope at 9,700ft. Slope 34 degrees. HS 250cm. The 3/10 interface didn’t produce any ECT, CT or DT tests. The 3/15 crust and 3/20 NSF each produced ECTN results. The layer of concern at this location was the 3/20 NSF once there is a slab, and if something did step down to the 3/15 crust it wouldn’t be much deeper at this location.

Date of Observation: 03/20/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Rec tour, several northeast facing slopes BTL

Observed avalanche activity: Yes
Avalanches: Skier triggered a loose dry avalanche that was large enough to push someone into a tree or terrain trap, entraining about 10″ of loose snow.
Weather: Snowfall rates alternated between light and moderate. Calm winds BTL.
Snowpack: About 6″ of pleasantly fluffy new snow by 4 p.m., on top of a low density, faceted interface. The upper 10″ or so sluffed easily on slopes steeper than about 38 degrees. No slab formation yet in the new snow, but once it does, there is a decent amount of snow for entrainment.

Date of Observation: 03/19/2023
Name: Lee Pownall

Zone: Southeast Mountains
Route Description: nacho, seldom seen, white widow, west whiterock, north white bench mark, red ridge over a couple days

Observed avalanche activity: Yes
Avalanches: Several nf shots in queens had cornice fall that tumbled close to 1000 feet before stepping down into p slab in extremely shady protected spots. West face whiterock had slid full track without stepping down. Some newer debris in the widow
Weather: Sunny. Springy, but not hot enough to really saturate anything. Enough wind to fill tracks in overnight
Snowpack: Extremely confusing. Some spots on the top of the compass had wind effect, most spots on the bottom of the compass had some sort of solar effect. Plenty of pow and it was ALL faceted. It was a crapshoot figuring out where the crust/facet sandwich was, my arms are tired from jabbing my pole thru layers.

My big takeaway…this next load will be extremely spooky, as there isn’t much continuity as far as aspect is concerned. Should be fun once it’s under a few more inches of swe

Date of Observation: 03/19/2023
Name: Zach Guy and Evan Ross

Zone: Northwest Mountains
Route Description: Snowmobiled to the south bowl of Baldy to get a closer look at the snowmobile triggered persistent slab from yesterday.

Observed avalanche activity: Yes
Avalanches: Huge! This was the biggest human-triggered avalanche that I’ve ever investigated and the most destructive slide we’ve seen this season since the Red Lady ran in early January. The crown was just under 2,000′ wide and ran about 1200′ vert, wrapping from south to southeast aspects near and above treeline. It is a hard slab that averaged about 5 feet thick. Some of the well-drifted areas were over 10 feet with a max crown depth of 15 feet. We estimate the debris pile was up to 30 or 40 feet deep. The snowmobiler remotely triggered the slide while ascending along a safe ridgeline. They weren’t sure exactly where the trigger point was; we estimate it was near a shallower spot near the top of the bowl, about 30 or 40 feet from the avalanche. We classified the avalanche: HS-AMr-R3-D3.5-O
Observed a handful of other small storm slabs and wind slabs that ran or were triggered sometime in the past few days, and one large persistent slab on a south aspect ATL near Avery Peak. See photos and details below.
Weather: Partly cloudy, mild temps, light winds with no transport observed.
Snowpack: The avalanche failed just above the March 10th crust, and was made up of drifted snow from the March 10th-11th storm and March 15th-16th storm. We dug one snow profile in a shallower part of the crown. See profile below. The weak layer is difficult to discern (~.5 mm rounding facets, 1F) and did not produce results in an extended column test. Grain sizes are slightly larger than the overlying slab, and one level of hardness softer than the overlying slab and underlying crust, both of which are pencil-hard. The snow surface at this location was 1.0 to 1.5 mm near-surface facets over a thin, soft crust.

Date of Observation: 03/18/2023
Name: Travis Guy

Zone: Southeast Mountains
Route Description: Skin track from Gothic Rd (Tuttle Cabin) to 3rd bowl on Snodgrass ridge

Observed avalanche activity: Yes
Avalanches: An avalanche on the rollover of 3rd bowl, which appeared to be skier triggered (tracks in)
Weather: Sunny but shaded in the bowl. Calm. -7C at Gothic townsite

Date of Observation: 03/19/2023

Zone: Northwest Mountains
Route Description: Yule Creek area

Observed avalanche activity: Yes
Avalanches: A few small triggered and natural wind slabs from northwesterly winds channeling down valley. A large persistent slab on the east side of Justice looks like it ran during the last storm.

Date of Observation: 03/18/2023

Zone: Northwest Mountains
Route Description: Mt Baldy SE face

Observed avalanche activity: Yes
Avalanches: Snowmobile triggered around 5pm today. No humans caught. More to come.