Date of Observation: 02/17/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Mineral Point, targeting wind slab instabilities on east to south aspects to 11,600′. Our plan was to cross under the south face of Mineral early morning before it got too warm. After several delays this morning (2 dead car batteries!), we didn’t cross beyond the most exposed sunbaked terrain until 11 a.m., which in hindsight, was cutting it too close for the type of terrain that we were on.

Observed avalanche activity: Yes
Avalanches: A large natural wind slab released off the south face of Mineral around 11:15 a.m., triggered by solar warming or perhaps a very tiny wet loose. The debris washed over part of our skin track that we had set an hour earlier.
Evidence of a widespread storm slab cycle in the Slate during the storm, along with numerous wind slabs in Poverty Gulch that ran after the storm, likely during yesterday’s northerly winds, up to D2 in size. See photos.
Weather: Clear, calm winds. Rapid warming; Double puffy snowmobile ride (-20F at TH), down to sun shirts once we started skinning. At one point, I looked over and my partner’s bare butt was showing, frantically trying to remove his long underwear. haha.
Snowpack: North winds did a lot of damage in Poverty Gulch, with wind slab formation scattered across all elevations. Wind slabs are easy to recognize: smooth, stiff snow (6″ to 12″ thick, 4F to 1F) below rollovers and in gullies, in contrast to softer, rippled sastrugi elsewhere. Wind slab feedback was stubborn underfoot. I snowmobiled and ski stomped on over half a dozen suspect wind-loaded rollovers without any signs of instability or cracking. However, I could produce cracks up to 5 feet while stomping on slopes undercut by the skin track. I also got easy test results on wind-drifted slopes (ECTP1, ECTPV). All of the wind slabs in this area, and my test results, failed on a low-density precip particle layer (non-persistent). Tests on the 2/13 storm interface were unreactive. I tested an east-facing slope near treeline which had a thin crust above facets at the storm interface.

Date of Observation: 02/16/2023
Name: Garrett Eggers

Zone: Southeast Mountains
Route Description: Skied the shoulder between first and second bowl on 2/16. Noticed a fairly wide crown through the trees on a NE aspect in first bowl that appeared to have entrained only the new snow. Probably ran naturally sometime on 2/15.

Observed avalanche activity: Yes

Date of Observation: 02/16/2023
Name: Andrew Payton

Zone: Southeast Mountains
Route Description: ESE chutes directly above Carbon Creek / CR737

Observed avalanche activity: Yes
Avalanches: Two avalanches observed on narrow and very steep east facing chutes on Carbon Peak around 130 pm. They ran about ½ mi / 1600’ vertical. I was cross country skiing up FR563 when I heard the long rumbles about 10 mins apart.

Weather: Sunny, 10 degrees

Date of Observation: 02/16/2023
Name: Rob Strickland

Zone: Southeast Mountains
Route Description: RL to RLB

Observed avalanche activity: Yes
Avalanches: Knocked the small cornice off the summit which produced a small slough and tiny slab… the wind was coming quickly from Redwell and building a small cornice on the south side at this time (730)… while skiing a small slab released naturally from the summit. Lower in the bowl another small slab was released on a steeper rollover.
No one was caught.
Slab size 2 – 4″ deep. maybe 50′ wide. D 0.5

Weather: Sunny & COLD

Date of Observation: 02/16/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Mount Axtell north 9,500-11,500. Evan’s Basin E-SE 9,500-11,300.

Observed avalanche activity: Yes
Avalanches: Looking out from Axtell I just noted a few old, small avalanches near ridgelines. Nothing notable stood out.

Red Lady Bowl looked to have a small wind slab that may have run today, otherwise, it was from yesterday.

One more small wind slab to add onto ZG’s ob that probably ran today in the Whetstone Group. East, 12,000ft.

Weather: Clear and cold. Snow plumes off the high peaks at times throughout the day, becoming more continuous in the afternoon.

Snowpack: On Mt Axtell, the upper snowpack had become notably stiffer when compared to yesterday, from the cold temperatures and previous wind effects. We skied steep slopes to around 40 degrees and didn’t encounter any storm slab avalanche problems. Sluffing was also minimal. Ski quality had decreased from yesterday, but was still good. Recent wind loading patterns are all over the place and not following a specific trend given all the variations in wind direction we have seen. Wind slab travel advice would have been more appropriate than a widespread storm slab avalanche problem today.

Over in Evan’s Basin, the conditions were similar. I didn’t encounter any unstable snow on this quick trip. Wind slab travel advice would have also been more appropriate in that terrain. I targeted a couple of test profiles on east and northeast-facing slopes to look at the 2/13 interface. On a 38-degree east-facing slope at 10,500ft, the 2/13 interface didn’t produce any results and didn’t look very concerning. On a cross-loaded 35-degree NE-facing slope at 11,000ft the 2/13 interface also didn’t produce any test results. Those small facets at the interface were still something to keep an eye on. The density change in the storm snow did produce test results, but snowmobiling through many steep test slopes didn’t produce any signs of instability.

Date of Observation: 02/16/2023
Name: Zach Guy

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

Observed avalanche activity: Yes
Avalanches: A handful of natural slab avalanches above treeline that ran during the storm, appear to be wind slabs ~D1.5

Date of Observation: 02/15/2023
Name: Eric Murrow

Zone: Northwest Mountains
Route Description: Slate TH on snowmo’s to Pittsburg. Tour along the Gothic Mountain Tour descent route off Elkton Knob.

Observed avalanche activity: Yes
Avalanches: Handful of small, natural avalanches failing midstorm depth. Remotely triggered three small avalanches on drifted terrain features at 10,900 feet, avalanches failed at the mid-storm interface.
Weather: Light snowfall and light winds in this area. Settled storm total of 17″ at 10,000 feet near Pittsburg and only about 10″ at the Slate River trailhead.
Snowpack: The storm snow was generally stubborn to human triggers in sheltered areas as the strong precipitation rates had ended before we were in the terrain but cracking up to a ski length was common. Drifted slopes remained very sensitive at the mid-storm interface into the afternoon and up to 2 feet thick. Digging into the west-facing slopes at the bottom of the Elkton Knob descent I found a facet/crust weak layer beneath the storm snow that was unreactive in snowpack tests and to human triggers (see photo). The slab above is not big enough in sheltered areas to collapse the underlying crust BUT could be on drifted terrain or in the future with further loading events. The drifted southwest-facing slope, at 10,900 feet, where I was able to remotely trigger small avalanches has a very strong crust, around 6 inches thick, below the storm snow.

Date of Observation: 02/15/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: AMR. 10,000ft to 11,500ft. N-E.

Observed avalanche activity: Yes
Avalanches: Fairly widespread natural storm slab cycle that likely occurred during the early AM hours. All small or D1 in size.

Weather: Headed out at 8:30 am and snowfall was tapering off over the next few hours. Mostly S1 to S-1 through that period. Mostly light winds with some moderate gusts out of the E-SE.

Snowpack: HST was ~50cm at 10,000ft. There was a notable density change in the storm snow that was responsible for all the avalanche activity that I was able to look closely at. In areas without notable wind-loading that weak layer was down anywhere from 10 to 30cm depending on elevation and how close to the Kebler Pass Trailhead. In the morning the storm slab avalanche problem was reactive, then by mid-day, it was becoming less reactive and trending towards stubborn.

Around 11,000ft there was notable previous drifting from the south side of the ridge to the north side of the ridge. Skinning on the south side of the ridge you were either walking on the old crusty snow surface or through thick wind wales.

Date of Observation: 02/15/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Rec tour on Mt. Emmons, traveling on northeasterly aspects below treeline.

Observed avalanche activity: Yes
Avalanches: Skier triggered a few thin storm slabs breaking on a density change mid-storm, D1 in size. Also observed several natural storm slabs that ran overnight, same character and size.
Weather: Light snowfall and light easterly winds both tapered to nil by this afternoon.
Snowpack: Storm total was up to 12″ on the small-grained near surface facet interface. There was a pronounced density increase in the storm snow that happened mid-storm, which was the source of today’s problems. Slabs cracking on this mid-storm weak layer ranged from 3″ to 8″ thick, depending on elevation. Higher elevations approaching treeline were more reactive.

Date of Observation: 02/15/2023
Name: billy barr

Zone: Southeast Mountains
Route Description: Gothic Townsite

Observed avalanche activity: No
Weather: The wind is the dominant factor as it makes things look (and feel) worse than they are. The heaviest snow was in a short period after dark but there was light snowfall yesterday afternoon and snowing most of the night with the 24 hour totals 4½” and water of 0.34″. Wind was stronger after midnight with steady 5-10 SW wind gusting to 20. Nothing massive on the wind but consistently irritating. Currently overcast with moderate SW wind and very light snowfall and the snowpack at 59″. billy