23-24

Recent Naturals in N. Bridgers

BRIDGER RANGE
Bridger Range
Code
N-R2-D2-O
Elevation
9000
Aspect
E
Latitude
45.85120
Longitude
-110.94800
Notes

On 2/1/24 GNFAC saw a wide crown in Frazier Basin and a similarly wide crown in another bowl to the north (300-400' wide), from the road with binos. Photos attached. not sure if these occurred recently with the above freezing temperatures or if they are older. they do not appear wet like the others, but I could not see the debris and was generally far away. Also they are in higher terrain favored for cooling effects. But, they easily could have occurred over the recent hot days, potentially triggered by cornice fall? Estimate they happened at start of warm up 1/28 or 1/29, possibly triggered from cornice fall. Ian saw the one to the north on 1/30/24 from Fairy lake area.

Number of slides
2
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
O - Old snow
Slab Thickness
20.0 inches
Vertical Fall
1000ft
Slab Width
420.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Recent Natural Wet slides in Bridgers

BRIDGER RANGE
Bridger Range
Code
WL-N-R1-D2-O
Elevation
8500
Aspect
E
Latitude
45.85120
Longitude
-110.94800
Notes

I drove up Bridger canyon this afternoon and stopped in a few spots to glass the range for recent avalanches. There were many recent wet avalanches, both wet loose that gouged through the snowpack and wet slabs about one foot deep and 50-100' wide. Many size D2, some smaller. Happened sometime between Monday and today (1-3 days old, maybe some this morning). The main spots for recent wet avalanches were on Bridger Peak and south of the Throne. Mainly on sustained steep terrain with rocky outcrops and east-south facing. There was one wet slab on a northeast facing, mid-elevation slope near the Throne. South facing terrain near Fairy Lake had some wet loose activity. I attached a photo of the wet slab activity on Bridger Peak and south of the Throne.

Number of slides
4
Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Natural trigger
R size
1
D size
2
Bed Surface
O - Old snow
Problem Type
Wet Snow
Slab Thickness
12.0 inches
Vertical Fall
800ft
Slab Width
100.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Bacon rind obs

Date
Activity
Snowboarding

Toured up bacon rind via the ridge ascent. Noted a small melt freeze crust below 7800’ with 2-3” above it. Low density snow capped a denser slab above the weak snow on the ground. signs of instability were less obvious than they have been. Still trigged several tree shaking collapses, with cracking up to 100ft above me. Riding quality was quite nice. 
noted a large avalanche that broke in the E,NE bowl off Ernest Miller, appeared to be hundreds of feet wide and several feet deep. 

Region
Southern Madison
Location (from list)
Bacon Rind
Observer Name
Riley Lindsey

GNFAC Avalanche Forecast for Fri Feb 9, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>The avalanche warning continues for the mountains around West Yellowstone and Island Park. Another 6” of snow yesterday with continued snowfall today combined with the 2-3 ft of snow that fell over the last week make both natural and human triggered avalanches likely. We’ve been warning you about the remarkably weak snow lower in the snowpack all season and it is now being put through its biggest test yet. It’s not handling it well. On Wednesday, snowmobilers in Tepee Basin triggered an avalanche from a distance that broke 4 feet deep and a mile wide (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30547"><span><span><span><strong><span… and video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). This is a huge avalanche, the biggest we’ve seen all season. Carefully ponder what it would mean to trigger a similar slide before even approaching the runout zone beneath a steep slope today.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Riding in Island Park yesterday, we saw no signs of instability such as cracking or collapsing, before we came upon a recent rider triggered slide (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=FPaaF7W2Mf8&amp;list=PLXu5151nmAvSH326z…;). As the weak layers get buried deeper, they will give less warning signs before avalanching. Don’t let this trick you. Don’t look for signs of instability to tell you to avoid steep slopes today - just make a plan to avoid riding on, or beneath, slopes steeper than 30 degrees and stick to that plan religiously. .</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is HIGH.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Another 1-2” of new snow around Bozeman, 4” in Cooke City and 2-6” around Big Sky are keeping avalanche conditions dangerous. With less recent snow, conditions aren’t quite as touchy as further south, but don’t take this as any sort of glowing endorsement of the stability, human triggered avalanches are still likely today. The snowpack has been incrementally loaded over the last week, keeping it teetering on the edge. Don’t be the thing that tips it over that edge. A natural avalanche and many collapses near Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30553"><span><span><span><strong><span… and photo</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30546"><span><span><span><strong><span…;) on Wednesday are clear signs the snowpack remains unstable. Natural avalanches earlier this week in </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30495"><span><span><span><strong><span… Basin</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30517"><span><span><span><strong><span… Range</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, and east of </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30537"><span><span><span><strong><span… City</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> are good examples of the sorts of slides you could trigger today.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Cautious route finding and conservative decision making are essential for a safe day in the backcountry today. Avoiding slopes steeper than 30 degrees is the best way to avoid triggering and being caught by a dangerous slide. Also be cautious passing beneath these slopes as you can trigger a slide from below.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

Small Snowmobiler Avalanche, Island Park

CENTENNIAL RANGE
Island Park
Code
SS-AM-R1-D1-O
Aspect
S
Latitude
44.54890
Longitude
-111.73100
Notes

A rider triggered a small avalanche in a steep gully. This avalanche was small in size but above a narrow gully. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
R size
1
D size
1
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
18.0 inches
Vertical Fall
20ft
Slab Width
40.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year