20-21

Natural avalanche (bison trigger?) in YNP near Cooke

Out of Advisory Area
Code
Notes

 

From obs: 3/6/21: "Observed several smallish avalanches in Yellowstone National Park today. The interesting thing about this one is the bison track that goes into the slide. No telling if the avalanche was triggered by the bison, but the shallow snowpack is about 1/2 faceted, so maybe it was remotely triggered. Resulting in a grizzly springtime snack??"

Number of slides
1
Number caught
0
Number buried
0
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From obs 3/6/21: "Observed several smallish avalanches in Yellowstone National Park today. The interesting thing about this one is the bison track that goes into the slide. No telling if the avalanche was triggered by the bison, but the shallow snowpack is about 1/2 faceted, so maybe it was remotely triggered." Photo: J. Logan

Out of Advisory Area, 2021-03-07

Two large deep slabs near Maid of the Mist

Maid of the Mist
Northern Gallatin
Code
HS-N-R3-D2.5-O
Elevation
10000
Aspect
E
Latitude
45.41150
Longitude
-110.98800
Notes

From obs 3/6/21: "Two large natural avalanches in Maid of the Mist Basin. One of them ran on the east face of Arden Peak (Peak 10,201) which propagated across the entire face. Could have been triggered by a cornice fall then stepped down to deeper layers. The second was on the NE face of the peak Fat Maid and Skinny Maid come from. Also propagated across the entire slope. Crown height between 6'-8' in most places." Timing of these slides is unknown. Probably in the last week, but maybe older.

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
2.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
48.0 inches
Vertical Fall
700ft
Slab Width
1000.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

From obs 3/6/21: "Two large natural avalanches in Maid of the Mist Basin. One of them ran on the east face of Arden Peak (Peak 10,201) which propagated across the entire face. Could have been triggered by a cornice fall then stepped down to deeper layers. The second was on the NE face of the peak Fat Maid and Skinny Maid come from. Also propagated across the entire slope. Crown height between 6'-8' in most places." Timing of these slides is unknown. Probably in the last week, but maybe older. Photo: S. Enloe

Northern Gallatin, 2021-03-07

From obs 3/6/21: "Two large natural avalanches in Maid of the Mist Basin. One of them ran on the east face of Arden Peak (Peak 10,201) which propagated across the entire face. Could have been triggered by a cornice fall then stepped down to deeper layers. The second was on the NE face of the peak Fat Maid and Skinny Maid come from. Also propagated across the entire slope. Crown height between 6'-8' in most places." Timing of these slides is unknown. Probably in the last week, but maybe older. Photo: S. Enloe

Northern Gallatin, 2021-03-07

Miller, Sunset, and Mineral

Date
Activity
Skiing

Quick observation from a beauty of a day in Cooke City. No obvious signs of instability noted throughout our tour today. Temps climbed into the mid 30s at upper elevations, but moderate southwest winds (cranking strong gusts on ridgelines) kept the surface snow cooler than expected. Mainly skied steep north facing shots with deep consistent snowpacks and the only moving snow was manageable surface sluffing and wind-driven spindrift. East, South, and West aspects all held 2-10cm sun crusts that were moderately supportable... while still frozen. South aspects corned up around noon above 9k'. Despite no new recent snowfall, there was still snow available for transport and leeward slopes were actively loading near ridgelines.

Additionally, we observed a handful of snowmobilers highmarking on 35+ degree North, East, and South facing slopes above 9k' showing no sluffing or obvious signs of instability from thier riding.

Thanks for the strong work fellas!

Region
Cooke City
Location (from list)
Sheep Creek
Observer Name
Zachary Stephen Miller

Wet loose in Beehive

Beehive Basin
Northern Madison
Code
WL-N-R1-D1-I
Elevation
9100
Aspect
SW
Latitude
45.34070
Longitude
-111.39100
Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Natural trigger
R size
1
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
Wet Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year