Date of Observation: 01/01/2023
Name: Irwin Guides

Zone: Northwest Mountains
Route Description: Irwin Tenure

Observed avalanche activity: Yes
Avalanches: Widespread Touchy Storm Slabs yesterday 12/31. There was a notable natural avalanche cycle on the Upper Upper West Wall that produced 3-5 large avalanches. This terrain has not been mitigated or skied this season and was predominantly scoured down to rock prior to 12/28. Lingering Storm Slabs were more resistant to explosive and skier testing in our core westerly terrain today. However, easterly start zones that were previously Unreactive reached a tipping point: a single hand charge cleared out almost all of Candies and Sonic to the ground (SS-AE-R2-D2-G FC (100cm x 75m x 150m)). This is southeasterly terrain from about 12k. We also had a small but impressive natural event today on The Crotch apron in a recently wind loaded pocket (HS-N-R2/D1.5-O/G 50-100 cm x 10m x 40m). This is SSW terrain at 11.8k and ran O/G with a crown of 1m at its apex.
Snowpack: We received 45″ of snow with 3.5 inches of water over two storm cycles since 12/28. The second cycle was notable for very warm temps, multiple riming events that laid down thin friable crusts at lower elevations, and several hardness inversions in the new snow.

Date of Observation: 01/01/2023
Name: Travis Tucker

Zone: Southeast Mountains
Route Description: A braap out to River’s End Campground from the Trading Post.

Observed avalanche activity: No
Avalanches: None observed.
Weather: Temp: H of 36*
Wind: Calm
Sky: Obscured (x)
Precip: S1 most of the day.
Snowpack: HS: 45 – 150cm
On a shallower North facing slope near road / Trading Post…
28 cm of 4F
7cm of 2-3mm FC
15cm of 3-5mm DH

CT15 SC down 28cm on 3-5mm DH
ECTP 18 “ “

Date of Observation: 01/01/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Snowmobiled Cement Creek to the base of Hunter Hill.

Observed avalanche activity: Yes
Avalanches: Widespread and ongoing natural and remotely triggered persistent slab activity that appeared to start last night and go through today, localized to Upper Cement Creek (east of Deadman’s Trailhead). In that upper basin, almost every single steep slope that we rode near remotely avalanched if it hadn’t already gone naturally. Dozens of small creek beds released, and we triggered about half a dozen larger slopes just riding in the flats. More natural avalanches than I could count. Crowns were generally about 2 feet thick, and most appeared to fail on the mid-December facet layer. Small terrain features produced D1-1.5s, and larger terrain produced D2s. Avalanches were occurring on all aspects, which are generally E, SE, W, and NW below treeline in this basin. Couldn’t see the alpine.
Weather: Light snowfall with a few moderate pulses. Calm winds below treeline.
Snowpack: This might have been one of the most widespread, touchy persistent slab days I’ve ever experienced in my career; truly fascinating and blatantly dangerous. Human triggering felt almost certain. Riding into open slopes consistently produced rumbling collapses with trees shaking hundreds of yards away, shooting cracks opening on moderate angled slopes, and almost everything steeper than 35 degrees would slide. Collapses occurred on mid-December facets and depth hoar, which are now in the bottom 3rd of the snowpack below a 60 to 90 cm slab. Tests produced sudden collapses on isolation in the depth hoar (ECTPV). Near the trailhead, I watched a small dog step off the road and trigger a shooting crack across a slope. In Lower Cement, slabs are thinner (~30 cm), and better anchored by ground roughness, sagebrush, etc, thus the danger was less threatening.

Date of Observation: 01/01/2023

Zone: Northwest Mountains
Route Description: Snowmobiling down the road.

Observed avalanche activity: Yes
Avalanches: Message from a friend up Bracken Creek that I thought I would pass along. Blue is where it slid, buried the road where the red mark is. Possibly triggered by snowmobiles but unconfirmed. That’s all the info I have.

Date of Observation: 01/01/2023
Name: Eric Murrow

Zone: Southeast Mountains
Route Description: Pavement views.

Observed avalanche activity: Yes
Avalanches: A brief view (too short a window to get photos or code individual avalanches) of numerous natural avalanches on the down valley end of Whestone. Northeast, east, and southeast aspects near and above treeline. The ground was showing in some of the bed surfaces and some appeared to propagate widely like in Lucky Boy Basin. Large natural avalanche observed above Long Lake at the Washington Gulch TH.
Weather: Consistent light snow after 1030am.
Snowpack:

Date of Observation: 01/01/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Ohio Pass.

Observed avalanche activity: Yes
Avalanches: Several large avalanches covered Ohio Pass Road. One of these ran yesterday reported by a group of snowmobilers. Unclear whether it was triggered or natural. The other two ran this morning.

Date of Observation: 01/01/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Mt. CB

Observed avalanche activity: Yes
Avalanches: Brief visibility this morning of large to very large avalanches on Whetstone and Gothic.

Date of Observation: 01/01/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Mt. CB

Observed avalanche activity: Yes
Avalanches: Brief visibility this morning of large to very large avalanches on Axtell, Augusta, and Scarp Ridge. Unfortunately, by the time I got to a good vantage of the Ruby Range, the clouds were back.

Date of Observation: 12/31/2022
Name: Benny Walter

Zone: Northwest Mountains
Route Description: Text message ob sent in from Elkton

Observed avalanche activity: Yes
Avalanches: East facing at 10,600 probably 40 degree slope remotely triggered from the tracks 200 feet to the lookers right. 50cmish at the crown 100 ft wide.

Date of Observation: 12/31/2022
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Lower Kebler Pass. Variety of aspects.

Observed avalanche activity: Yes
Avalanches: Few small storm slabs.

Weather: Overcast. Light down-valley winds in the afternoon. Snowing S1 to S2

Snowpack: Quick tour, mostly targeting some NE slopes BTL in lower Elk Creek. Other than a few small storm slabs, nothing notable in the lower Elk Creek area or near the road on Kebler. Traveled on several small test slopes, and near-defined avalanche terrain with no obvious signs of instability.

ENE, 31-degree slope, BTL that does see wind-loading. HS 153. The recent storm interfaces were down about 15cm and 25cm. December 20th was down about 70cm. ECTP 3 on the lower storm interface. ECTN 24 on 12/20. The 12/20 interface was very thin and difficult to see in the pit wall, but still defined 1mm NSF on the card.