Northern Gallatin

Small wind slab slide on Elephant Mountain

Date
Activity
Skiing

Started a small wind slab avalanche on an isolated rollover about 2/3 of the way down the face of elephant mountain yesterday (Thursday January 12th). Broke a few inches deep, about 8 feet wide, and ran less then 100 ft. 

Region
Northern Gallatin
Location (from list)
Elephant Mountain
Observer Name
Trevor grab

Small skier triggered windslab in Hyalite

Maid of the Mist
Northern Gallatin
Code
SS-ASu-R2-D1
Elevation
10000
Aspect
N
Latitude
45.41640
Longitude
-110.97000
Notes

From obs:

While skiing down 'Fat Maid' I triggered a shallow wind slab, after I was about 3/4ths of the way down the couloir. The slide broke to my left as I entered a wider section of the run, that holds a small perched bowl feature (which is what ripped out). The slide didn't propagate out into the main couloir, so the debris never impacted me. Even if it had, I don't think it would've been big enough to knock myself or any other skier off their feet. The slide was about 1/2 the width of the couloir and ran out to about 3/4ths of the apron's length (R2 D1?). The crown was 1-3" deep and maybe 30-40' wide. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
2
D size
1
Problem Type
Wind-Drifted Snow
Slab Thickness
2.0 inches
Vertical Fall
100ft
Slab Width
30.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Skier Triggered Windslab Avalanche in Maid Basin

Date
Activity
Skiing

Today my partner and I set out to ski Divide Peak and then re-ascend to connect the ridge over to 'Fat Maid' in Maid of the Mist basin. On our way up Divide peak, a hasty pit yielded poor results so we decided to bail on the main SE Gully that leaves from the summit. We still skied down from the shoulder, in the trees, and continued on our plan to head back up and over to Maid.

While skiing down 'Fat Maid' I triggered a shallow wind slab, after I was about 3/4ths of the way down the couloir. The slide broke to my left as I entered a wider section of the run, that holds a small perched bowl feature (which is what ripped out). The slide didn't propagate out into the main couloir, so the debris never impacted me. Even if it had, I don't think it would've been big enough to knock myself or any other skier off their feet. The slide was about 1/2 the width of the couloir and ran out to about 3/4ths of the apron's length (R2 D1?). The crown was 1-3" deep and maybe 30-40' wide. Had the wind slab been larger, or impacted one of the thin faceted layers mid-pack (like the one that scared us off Divide Peak) it could've been a different story. Thought it'd be good for people to consider heading into the weekend and unsettled weather. The picture is kinda hard to see so I did quickly draw the crown on the same image, but will send you the original as well. 

On another note, we found an impressive amount of surface hoar, widespread, even in alpine areas exposed to sun and wind. Hopefully it get knocked down before the next storm! 

Region
Northern Gallatin
Location (from list)
Maid of the Mist
Observer Name
Christopher Kussmaul

Natural avalanche near Moose Jaw creek

Moose Jaw
Northern Gallatin
Code
SS-NC-R1-D1-O
Latitude
45.44940
Longitude
-111.07600
Notes

From Obs: "Observed recent small wind slab avalanches under the ridgeline as well as one larger slide that broke on weak snow near the ground, likely caused by cornice fall."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Cornice fall
R size
1
D size
1
Bed Surface
O - Old snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Blackmore Lake, NE Aspect

Date
Activity
Skiing

Yesterday we tested and skied a well-protected, NE-facing line above Blackmore Lake. There were strong winds during our approach and we observed evidence of wind loading on northern aspects. By around 2 pm, wind speed and wind loading reduced significantly. At our pit location, we observed a thin wind crust (1-2cm) that moved quite readily. This layer did not move during stability tests and did not propagate while skiing, but released readily while skiing. At the bottom layer of the snowpack, we noted that the grain size increased since our visit to the area last weekend, and the faceting in this layer was much more apparent particularly at the bottom of the layer (see photo). 

Region
Northern Gallatin
Location (from list)
Mt Blackmore
Observer Name
Erich Schreier

Recent natural avalanche activity near Moose Jaw creek

Date
Activity
Snowboarding

Observed recent small wind slab avalanches under the ridgeline as well as one larger slide that broke on weak snow near the ground, likely cause by cornice fall. 

Region
Northern Gallatin
Location (from list)
Moose Jaw