23-24

Natural deep slab avalanche, Flanders Mtn

Flanders Creek
Northern Gallatin
Code
HS-N-R3-D3-O
Elevation
9800
Aspect Range
E-NE
Latitude
45.43600
Longitude
-110.94200
Notes

We toured up to Flanders Mtn. to take down the weather station for the season (before the road closes on Monday, Apr 1). The main observation is a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. Photos and video attached. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O. 

 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
3
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

We toured up to Flanders Mtn and saw a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O.  Photo: GNFAC

 

Northern Gallatin, 2024-03-30

We toured up to Flanders Mtn and saw a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O.  Photo: GNFAC

 

Northern Gallatin, 2024-03-30

We toured up to Flanders Mtn and saw a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O.  Photo: GNFAC

 

Northern Gallatin, 2024-03-30

We toured up to Flanders Mtn and saw a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O.  Photo: GNFAC

 

Northern Gallatin, 2024-03-30

We toured up to Flanders Mtn and saw a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O.  Photo: GNFAC

 

 

Northern Gallatin, 2024-03-30

Natural deep slab avalanche

Date

We toured up to Flanders Mtn. to take down the weather station for the season (before the road closes on Monday, Apr 1). The main observation is a big, deep 2-6' deep avalanche that broke 300-500' wide in weak snow at the bottom of the snowpack. Photos and video attached. It broke across two separate start zones and included a lower angle ridge (still around 30 degrees) in between that slid. E-NE aspect at 9,800'. HS-N-R3-D3-O. 

Next to the avalanche debris there was 1-2" of new snow on a thin melt-freeze crust, and the debris seemed to have around 3" of new snow on it. Minimal evidence of recent wind.There was a trace of new snow in the parking lot, 3-6" on most of the trail, I think from the last couple days, and places up high had 10-12" of recent snow where the sun hadn't affected snow from earlier in the week. Today wind was calm with sunny skies becoming partially obscured with light snow showers. We also saw one small dry loose slide in the new snow on a steep north facing slope, and a variety of older crowns including wind slabs near the ridge and one 2-3' deep crown below some cliffs.

 

Region
Northern Gallatin
Location (from list)
Flanders Creek
Observer Name
Alex Marienthal

Beehive basin pits

Date
Activity
Skiing

Today, myself and 5 others toured up beehive basin for an avalanche 2 course. In the morning a pit was dug in the bonus wiggles on a south facing slope. The biggest takeaway from this was the melt freeze crust on the surface. This pit experienced an ECTP-22 and CT-15-Q1. Both tests failed on depth hoar 40 cm above the ground. Another pit was dug on an east facing slope on the west side of beehive basin in an opening between tree fields, about 30ft from the ridge line. The biggest takeaways from this pit where a PST 40/120-end at the surface hoar-melt freeze crust interface 40cm above the ground and ECTN on the upper crust. As for the surface, the surface crust softened for the afternoon decent. There was little to no wind today and no evidence of wind slab, no observed avalanches, and no observed cracking or collapsing. 

Region
Northern Madison
Location (from list)
Beehive Basin