Date of Observation: 12/12/2021
Name: Zach Guy

Zone: Southeast/Northwest Mountains boundary
Route Description: Mount Emmons. Traveled mostly on S and SE aspects to 12,400′

Observed avalanche activity: Yes
Avalanches: Adding a pile of previously undocumented naturals to the list from the recent cycle that fit the pattern of what we’ve been observing, see photos and details below. Most of the northeast side of Red Lady Bowl appeared to run and there were a handful of wind slabs that ran on the southeast portion of the bowl. I didn’t see any fresh avalanches from the past 24 hours.
Weather: Sunny, clear. Winds were strong enough to blow my #tired hat off my head, but luckily I retrieved it. Snow transport continues above treeline in exposed locations.
Snowpack: Our field objective today was to assess if the persistent slab problem should expand to the sunny aspects that held a crust (rather than dirt) before the storm. In short, I didn’t find evidence of persisting issues on the 12/6 crust where it is stout on sunny aspects. In a pit on a SE aspect NTL, long column tests produced no concerning results on the crust. The crust is pencil hard and goes to the ground where we dug. Above the crust, there are .3 to .5 mm rounding facets, 4F- (the 12/8 layer).
We traveled mostly on sunny slopes that were dirt before the storm with no signs of instability. As soon as we scooted into some low angle, shady terrain below treeline, we started getting collapses that would radiate to the nearest cluster of trees. These same slopes are developing small grained surface hoar and near-surface facets on the snow surface right now. Kicked at a few recent drifts at higher elevations with minimal cracking.

Date of Observation: 12/11/2021
Name: Eric Murrow

Zone: Southeast Mountains
Route Description: Standard up-track on Snodgrass and ridge walk towards Third Bowl.

Observed avalanche activity: Yes
Avalanches: On the north side of Snodgrass, many steep, open features avalanched naturally during the storm. Some ran early with up to 16 inches of refill on bed surface and others failed late with 6 inches of refill.
Weather: Clear skies with cool temperatures and relatively light winds (I was below treeline for my tour, but did observe some drifting occurring above treeline on east, southeast, and south aspects)
Snowpack: On the north side of Snodgrass, snow depths were around 3 feet deep. Recent storm snow has settled to about 2 feet. Numerous muffled, small collapses while walking across low-angled slopes that had previously collapsed and shattered naturally during the storm. Several large, louder collapses while moving through low-angled northerly terrain without evidence of previous collapsing that traveled up to 100 feet. I dug one profile in a location with an intact snowpack and another on the bed surface of a natural avalanche that ran early in the storm. Northerly-facing slopes that have not avalanched remain very sensitive to the weight of a person.

Photos:

Date of Observation: 12/11/2021
Name: Harry V. L.

Zone: Southeast Mountains
Route Description: Slate. Not very far. As it turns out, old sleds are not as good as new ones. To have enough money to buy a good snowmobile would be nice… Anyway, we went up Gunsight on a walkaround.

Observed avalanche activity: Yes
Avalanches: We assumed that many of the recent activity in the alpine was drifted in and/ or filled back in with the last spurts of snow yesterday afternoon. However, we were confident there were many which had filled in and weren’t visible… On our little walk up Gunsight we were able to easily produce reactive results on anything and everything. Pretty much everything that was remotely steep enough to slide had already gone to ground, or at least fractured to ground. Luckily we found one switchback that was primed to go and it barely took the weight of a ski to send it to ground (see picture). Skied a few meadows on the descent and it was a symphony of whoomphs.
Weather: Cold. Car said -9 at around 9am. Upon return, car read 4 at 2pm. We observed flagging off everything above treeline all day. Obviously windy in the alpine, seeminly due west. No wind BTL on N.
Snowpack: Well, a lot of adjectives. We were walking on shady N facing aspects primarily… So, unsupportive, unconsolidated, noisy, reactive, etc. Ski pen was close to ground and boot pen was basically to ground… No surprises there.

Date of Observation: 12/11/2021
Name: jeff banks

Zone: Southeast Mountains
Route Description: 9600-10,800

Observed avalanche activity: No
Avalanches:
Weather:
Snowpack: Dug on SSW-W-N aspects 9600-10,800

SSW-SW: Storm snow well bonded to the ground & itself, unreactive (HS 60cm, Fist to 4F, block sticks to leaves & grass when pried off)

W: Storm snow well bonded to thin crust on the ground, unreactive.

Shaded by Evergreens: Also well bonded to melt freeze crust. Occasionally, small, isolated pockets of facets and the storm slab was poorly bonded but small ski length cracks underfoot.

N: Wind loaded, shooting cracks traveling ~20 ft

Date of Observation: 12/12/2021
Name: Travis Colbert

Zone: Northwest Mountains
Route Description: Went for peaceful ski on a flat forested trail where the only sounds were the frequent rolling collapses that would shake the snow from a tree 40 feet away and the gentle buzzing of faraway two-strokes at the Kebler trailhead. The high point of my tour was a portal to a much different world. Most of the terrain above Green Lake had slid, taking out much of the season’s snowpack. Tread carefully out there!

Observed avalanche activity: Yes
Photos:

Date of Observation: 12/11/2021

Zone: Northwest Mountains
Route Description: Toured a south/southwest face in the northwest mountains. Snow was wind effected at all elevations. Ski pen was about boot top on the ski up. No signs of instability on our ski but we did not venture into any shady or north aspects.

Observed avalanche activity: Yes
Avalanches: Widespread avalanches, mostly on north and east aspects. Most interesting was a fairly large avalanche at the top of the Pittsburg Rollers. Purple ridge had avalanches everywhere.
Weather: sunny, windy. moderate winds BTL higher winds ATL
Snowpack: Wind effected at all elevations

Date of Observation: 12/11/2021
Name: Evan Ross

Zone: Southeast Mountains
Route Description: Huge thanks to West Elk Air for getting the CBAC team views of the carnage. These photos are from Brush Creek area

Observed avalanche activity: Yes
Avalanches: The avalanche activity was much harder to see in the SE Mountains, compared to the NW Mountains. The avalanche activity in the SE Mountains was less widespread, smaller in size, and often hidden by wind-loading or additional snow after the storm.

The primary avalanche activity was on NE at all elevations. East, had activity at near and above treeline elevations and some suspicious-looking slopes below treeline but nothing that could be confirmed at that elevation.

South had activity above treeline, but again far less than the NW Mountains. I suspect that was to do with more south-facing slopes in this area having been dry before this storm.

West and North aspects were well shaded. If there was avalanche activity on those aspects, it couldn’t be confirmed on this flight.

Photos:

Date of Observation: 12/11/2021
Name: Evan Ross

Zone: Southeast Mountains
Route Description: Huge thanks to West Elk Air for getting the CBAC team views of the carnage. These photos are from the Mt. Emmons and Snodgrass area.

Observed avalanche activity: Yes
Avalanches: The avalanche activity was much harder to see in the SE Mountains, compared to the NW Mountains. The avalanche activity in the SE Mountains was less widespread, smaller in size, and often hidden by wind-loading or additional snow after the storm.

The primary avalanche activity was on NE at all elevations. East, had activity at near and above treeline elevations and some suspicious-looking slopes below treeline but nothing that could be confirmed at that elevation.

South had activity above treeline, but again far less than the NW Mountains. I suspect that was to do with more south-facing slopes in this area having been dry before this storm.

West and North aspects were well shaded. If there was avalanche activity on those aspects, it couldn’t be confirmed on this flight.
Weather:
Snowpack:

Date of Observation: 12/11/2021
Name: Ben Pritchett

Zone: Northwest Mountains
Route Description: Axtell as viewed from town

Observed avalanche activity: Yes
Avalanches: Couldn’t see 1st bowl well, but a few small ones below the skiers’ left cliffs. 2nd Bowl had broad-spanning soft slabs connecting the start zones a couple hundred feet below the ridgeline. Eraser and Pencil start zones both went, also well below ridgeline. That pocket feature between Wang Chung and 4th bowl went broadly. 4th bowl went R3, stopped just before the Shield. Green Lake Bowl from near the Eraser through the middle of the cliffs, looked early, kinda filled in. At least two of the Green Lake Chutes ran to the apron.

Date of Observation: 12/11/2021
Name: Zach Guy

Zone: Northwest Mountains
Route Description: Various from Axtell, Copper Creek, Peeler Basin, etc

Observed avalanche activity: Yes
Avalanches: See photos.