Date of Observation: 05/09/2023
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Red Ridge to Queen Basin to Whiterock Mtn

Observed avalanche activity: Yes
Avalanches: Skier triggered and observed a few fresh natural wet loose avalanches on high, north-facing terrain up to D1.5 in size.
Numerous previously undocumented wet slabs from the April cycle, D2-D3. I’ll document those in a separate ob later this week.
Weather: Clear to few clouds, warm temps, light breeze.
Snowpack: Wet loose avalanches became reactive to ski cuts by mid day on ATL northerly terrain, where the top 6″ of dry powder was just now transitioning to wet snow. Elsewhere, the snow surface has matured through numerous melt-freeze cycles and wet loose avalanches appeared to be unreactive, even on steep terrain late in the day. The snow surface remained supportive to skis through 4 p.m. at all elevations except for a few spots near evergreen trees below treeline.

Date of Observation: 04/28/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Upper Slate and Yule Pass areas. Traveled mostly on easterly and northerly aspects to 12,600′

Observed avalanche activity: Yes
Avalanches: On north-facing terrain ATL, I skier triggered a thin wind slab (~6″ x 8′) and a loose dry avalanche that both ran about 800′ (D1s).
Wednesday’s sunny weather after the storm spurred a wet shed cycle around the compass except for high northerlies. These were mostly wet loose, D1-1.5, and a handful of slabs up to D2. Not sure if they were moistening storm slabs or wet slabs; the debris looked fairly wet.
Weather: Clear, unseasonably cool temps. Moderate northwest winds were blowing the 1″ of new snow around with small plumes off of high peaks.
Snowpack: 1″ of new overnight and winds formed isolated, thin wind slabs ATL. These appeared to be bonding well on solar aspects; got one to pop on a crossloaded north facing slope. There’s up to 10″ or so of recent storm snow from the Tuesday night storm which hasn’t fully transitioned yet and could continue to produce more wet loose activity this weekend, especially to human triggers. At 1 p.m. while skinning up Yule Creek (~10k’, fairly flat terrain), we were getting widespread collapses on the dust layer, which was about 6″ to 8″ deep and saturated. Most collapses were a ski length or two wide, but some produced shooting cracks up to 30′ or 40′. This suggests there is potential for thin wet slabs this weekend as well, similar in character to the avalanches on Schuylkill Ridge shown below.

Date of Observation: 04/22/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: NE-E-SE 9,500-11,500. Purple Ridge Area.

Observed avalanche activity: Yes
Avalanches: At 1pm, wet loose avalanches were reactive on NE and E below 11,300ft. These were generally small, but where they could run and accumulate mass they became large in size. We skier triggered several small wet avalanches and one become large in size. Another party had triggered more wet avalanches in similar terrain.

Weather: Convective snow showers with some moderate winds and drifting snow during those periods. The greenhouse was in full effect.

Snowpack: Recent storm totals were around 20 to 25cm at 11,000ft. Less snow at lower elevations and more snow at higher elevations… On the lee side of Purple Ridge, the drifts were a couple of feet thick. It was difficult to assess how far the thicker drifts extended into the slopes below. Wind slabs felt stubborn, but there was a notable lower-density layer of snow near the bottom of the drifts.

Snow surfaces become moist to wet on the sunny aspects, and thick/moist on northerlies BTL.

Date of Observation: 04/19/2023
Name: Eric Murrow

Zone: Northwest Mountains
Route Description: Kebler Pass road up to Scarp Ridge.

Observed avalanche activity: No
Avalanches: none
Weather: Light snowfall with obscured views. Strong southwest winds.
Snowpack: At 330pm, storm totals were less than 2 inches.  Snowfall rated increased as I left the area.  Strong winds blasted the snow towards leeward terrain features. The lowest-elevation terrain, below 9,500 feet, snow surfaces were soft from mild-ish temperatures but did not pose a loose avalanche threat. I dug a quick hole on a north-facing slope immediately adjacent to Crested Butte and found meltwater had drained 2+ feet into the snowpack. There was still some free water present. I do not expect this to create any avalanche concerns; I was simply checking on how deep meltwater has drained on the warmest north-facing slopes.

Date of Observation: 04/17/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Baxter Basin, North to 12,000ft.

Observed avalanche activity: Yes
Avalanches: Difficult to tell if there have been more natural loose wet avalanches since yesterday. Nothing notable stood out.

Weather: Few clouds, hot, calm wind.

Snowpack: Due north was dry and provided great skiing with minor sluffing in steep terrain. Just about everything else was looking hot and not inviting in the afternoon. NE slopes had gone through a shed cycle where they were steep and rocky. Lower elevation NE slopes had a shiny appearance from a distance.

Date of Observation: 04/17/2023
Name: Evan Ross

Zone: Northwest Mountains
Route Description: Poverty Gulch near Pittsburg.

Observed avalanche activity: Yes
Avalanches: This avalanche was previously reported and ran on 4/12.

This wet slab was triggered by a wet loose avalanche from above. In total, it ran 800 vertical feet, though the slab only ran about 400ft. It was surprisingly destructive. In the debris there were many aspen trees, maybe 30 to 50, and there were about 10 mature pine trees. This slope had several wet loose avalanche events in the couple of weeks before it ran as this wet slab.

Date of Observation: 04/16/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Purple Ridge to 12,200′. Easterly and northerly aspects.

Observed avalanche activity: Yes
Avalanches: Numerous small wet loose avalanches ran at all elevations, predominantly on east and southeast aspects this morning (D1s). A few reached around to NE aspects BTL. These all ran on the dust/crust layer. We skier triggered a couple of similar avalanches and observed other skier triggered slides as well. Skier triggered one hot wind slab that entrained wet loose snow on a crossloaded gulley below treeline (D1).
Weather: Light ridgetop winds, minor transport. Clear skies. Springlike temps.
Snowpack: Settled storm snow depths ranged from 4″ to 8″, notably redistributed by wind in this area.
Targeted a few windloaded test slopes and could only get localized cracking with no releases, until we got one wind slab to pop later in the day in a steep chute. Drifts were up to 2 feet thick below large fetches, but the cracking was occurring on a mid-storm layer about 6″ to 8″ deep.
Mid to high northerlies stayed dry, with wet loose activity beginning mid-morning on easterlies. The 4/14 interface stayed frozen and supportive to ski pen through midday.

Date of Observation: 04/16/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Viewed from Slate River Road and Purple Ridge.

Observed avalanche activity: Yes
Avalanches: Schuylkill Ridge saw a wind slab cycle (averaging D1.5) on crossloaded terrain from Northwest winds yesterday. Several other soft slabs above treeline ran during or after the storm yesterday.

Date of Observation: 04/16/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Upper Slate area

Observed avalanche activity: Yes
Avalanches: A few more previously undocumented wet slabs. These ran sometime after Evan was in the area mid-day on 4/12, so likely the afternoon of 4/12 or sometime 4/13.

Date of Observation: 04/15/2023
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Mt. Axtell Green Lake Bowl

Observed avalanche activity: Yes
Avalanches: D2 cornice fall above Green Lake, likely yesterday or today.