23-24

Observed on 02/19/2024: From obs: "From the approach trail to Mummy II we saw two large crowns on the ridge associated with Mt. Bole. Not sure when they happened, but they looked pretty big!" Photo: M. Bjornsson

Northern Gallatin, 2024-02-20

Remote Triggered Avalanche, Pioneer Mountains

East Pioneer Mountains
Dillon Area
Code
HS-ASr-R3-D2-O
Elevation
9100
Aspect
NE
Latitude
45.46230
Longitude
-112.96100
Notes

From obs: "Accessed low angle settled powder runs via mellow ridge terrain adjacent to a known avalanche path which is steep, rocky and windloaded. We descended on lower angle terrain following uptrack. On second lap observed the crown and debris while climbing uptrack and suspected we remote triggered; it was not there on first lap. Slope angle 35-38 degrees estimated. Estimate crown depth 60-120 cms. Estimated debris depth 2-3 meters due to terrain trap of an abrupt transition to flat terrain at bottom of path. We did not approach the crown or debris due to hangfire. Starting Zone NE facing at 9100' on wind loaded convexity with unsupported terrain below and rocky bed surface and exposed rocks/cliffs. I would classify it as HS-ASur-R4-D2.5-O

Large collapses with cracks connecting weak spots in the snowpack for 50 feet around us while breaking trail. Slab has gotten quite a bit thicker and more cohesive with 3 inches SWE in past 14 days combined with relatively warm temps promoting settling, strong solar input on the southerlies, and some wind. Average snow depth 100 cms consisting of a F-1Fslab on top of 20-30 cms of large facets. A crust in between on solar aspects. There is a density break/layer of NSF in the slab you can see in some of the photos where it appeared to shear between those layers. A very scary snowpack even for the Pioneers which regularly harbor PWLs throughout the season."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Skier
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
80.0 centimeters
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Skiers in the Pioneer Mountains remotely triggered this avalanche on 02/19/2024. From obs on 02/20/2024: "We descended on lower angle terrain following uptrack. On second lap observed the crown and debris while climbing uptrack and suspected we remote triggered; it was not there on first lap" Photo: A. Dunn

Dillon Area, 2024-02-20

Skiers in the Pioneer Mountains remotely triggered this avalanche on 02/19/2024. From obs on 02/20/2024: "We descended on lower angle terrain following uptrack. On second lap observed the crown and debris while climbing uptrack and suspected we remote triggered; it was not there on first lap" Photo: A. Dunn

Dillon Area, 2024-02-20

Rider Triggered Avalanche near Lulu wx station

Fisher Mtn.
Cooke City
Code
AMr
Latitude
45.06610
Longitude
-109.95900
Notes

Riders triggered an avalanche near fisher peak on 02/17/2024. Reported on 02/18/2024

Number of slides
1
Number caught
0
Number buried
0
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Rider Triggered Avalanche, Crown Butte

Crown Butte
Cooke City
Code
AMr
Latitude
45.05250
Longitude
-109.96200
Notes

Riders triggered an avalanche remotely on Crown Butte. Reported on 02/18/2024

Number of slides
1
Number caught
0
Number buried
0
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year