23-24

Skier triggered loose snow in Beehive Basin

Beehive Basin
Northern Madison
Code
L-AS-R1-D1
Elevation
9400
Aspect
W
Latitude
45.33430
Longitude
-111.38600
Notes

Multiple natural avalanches and at least one suspected human triggered dry loose in Beehive Basin. Most naturals appeared to have run either last night or yesterday (2/3/24), with a couple potentially older slides. New snow and rapidly changing cloud cover/depth perception made it a bit hard to be sure. Suspect one skier trigged dry loose in W facing trees. One of the W-facing chutes further up valley was also observed to have a crown line at approximately 9000' (no photo)

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Skier
R size
1
D size
1
Problem Type
New Snow
Images
Beehive avalanches
Snow Observation Source
Avalanches in Beehive Basin
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
23-24

Very Poor Stability at Bacon Rind

Date
Activity
Skiing

The stability at Bacon Rind was very poor, avalanches were likely, and we avoided (and strongly recommend avoiding) avalanche terrain. We triggered booming collapses and watched cracks shoot out across terrain features and snow shake off nearby trees for the entirety of our tour from the meadow near the car to the top of the Skillet. We avoided steeper meadows and gave the "Skillet" (the primary avalanche path where we were) a wide berth because we felt triggering a slide was so likely. 

There was 8" of new snow. The upper half of the snowpack was a slab, and the lower half was airy depth hoar stressed to the point of failure. Snowpit results were ECTP11 and 12 failing 35cm down from the surface. As we have noted previously, do not trifle with this season's snowpack. It is exceptionally weak and will be slow to stabilize based on all evidence thus far this season. 

Region
Southern Madison
Location (from list)
Bacon Rind
Observer Name
David Zinn

Instability in Northern Bridgers

Date
Activity
Skiing

Toured up near fairy lake today. Several natural avalanches on Pomp, Sac, and Naya Nuki. Numerous whumphs traveling through the meadows. Did a quick pit on an eastern aspect at 8000'. HS110cm. ECTN8 at the melt freeze crust 95cm and ECTP21 at 65cm on some 1-2mm facets. By about 10:30AM winds were picking up and we boogied out of there.

Region
Bridger Range
Observer Name
Sam Lowe

Unstable snowpack near Cooke

Date

We skied south of Cooke City and dug a snowpit at 9,761' on a west facing slope. We had an ECTP21, 40 cm below the surface (16" down). There was 6-8" of new snow from the weekend above 4" of soft old snow, on top of 4" of a pencil- hard slab, then the soft sugary facets to the ground. ECT broke below the hard slab at the top of the facets (photo). I had one collapse, 10-12' wide near treeline where there was little more wind-loading/effect (photo). 

The unstable test score, very poor snowpack structure, and collapse indicate a person could easily trigger a large avalanche on steep slopes.

Snowed lightly on and off all day with a couple cm accumulation. Wind was light-moderate out of the southwest with mostly overcast skies.

Region
Cooke City
Location (from list)
Republic Creek
Observer Name
Alex Marienthal

Pits from the Ramp

Date
Activity
Skiing

I did some digging around on the Ramp this morning. Got propagating test scores with moderate force in 3 snowpits. Pit from just below the ridgeline on an East aspect at 8500' had a snow height of 120cm: ECTP16 down 60cm, interface between 4f facets and larger fist facets. A thin, soft 1cm MF crust was present down 15cm. I dug at 8000' on a South aspect, height of snow was 60cm, ECTP11 down 30cm below a 20cm MF crust, wet depth hoar to the ground. I also dug on a SE aspect at 8200', height of snow was 65cm ECTP13 down 40cm on dry depth hoar below a 15cm MF crust.

Except the top 200', a stout MF crust was near widespread below the new snow. Tracks in steeper terrain showed small loose dry slides contained to the new snow. It was warm, southerly aspects were getting wet by mid day, wind was light, I didn't observe any evidence of transport. 

Thanks for all your hard work!

Spencer

Region
Bridger Range
Location (from list)
The Ramp
Observer Name
Spencer Jonas

From obs 2/4/24: "Multiple natural avalanches and at least one suspected human triggered dry loose in Beehive Basin. Most naturals appeared to have run either last night or yesterday (2/3/24), with a couple potentially older slides. Suspect one skier trigged dry loose in W facing trees..." Photo: M. Zia

Avalanche Details: Skier triggered loose snow in Beehive Basin
Forecast link: GNFAC Avalanche Forecast for Mon Feb 5, 2024GNFAC Avalanche Forecast for Tue Feb 6, 2024
Northern Madison, 2024-02-05
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    • GNFAC Avalanche Forecast for Mon Feb 5, 2024

    Snowpack and Avalanche Discussion

    <p><span><span><span><span><span><span>Wind increased overnight and drifted new snow into heavier slabs on an unstable snowpack. Today, more new snow and wind will continue to grow drifts, and make natural and human-triggered avalanches likely. Over the last two days in the southern Madison Range multiple groups of skiers experienced large collapses of the snowpack (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30474"><span><span><span><strong><span… 1</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/30485"><span><span><span><strong><span… 2</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/30484"><span><span><span><strong><span… 3</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Near Island Park, yesterday a rider noted a foot of new snow, strong wind and large collapses (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30490"><span><span><span><strong><span…;), and on Friday a rider triggered an avalanche and was partially buried while riding solo. He was thankfully able to dig himself out unharmed (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30469"><span><span><span><strong><span…;). Conditions will be more dangerous today. Avalanches can be triggered from flatter terrain connected to steeper slopes above. Plan your day carefully. Choose routes that avoid travel on or underneath slopes steeper than 30 degrees. The avalanche danger is HIGH.</span></span></span></span></span></span></p>

    <p><span><span><span><span><span><span>Over the last couple days the mountains near Bozeman, Big Sky, and Cooke City received 5-8” of new snow (0.4-0.7” of snow water equivalent). Strong wind is drifting this snow into thicker slabs that will easily avalanche. Avalanches will probably break deeper on weak layers buried 1-2 feet deep, and can be triggered from flatter terrain below steep slopes.</span></span></span></span></span></span></p>

    <p><span><span><span><span><span><span>Yesterday, in Beehive Basin skiers saw recent natural and skier-triggered loose snow slides (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30495"><span><span><span><strong><span… and details</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>), a skier south of Cooke City sent this </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30491"><span><span><span><strong><span…; of a recent large natural avalanche, and north of Cooke City we found unstable buried weak layers below a hard slab of snow (</span></span></span></span></span></span><a href="https://youtu.be/c7XwPvZ93ZU?feature=shared"><span><span><span><strong>…;). Previous avalanche activity near Cooke City was widespread and shows the type of avalanches a person can trigger (</span></span></span></span></span></span><a href="https://youtu.be/gJtR7y1kYuU?feature=shared"><span><span><span><strong>… update video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Earlier this week, ice climbers approaching a climb triggered a large slide from 150 feet away (</span></span></span></span></span></span><a href="http://www.mtavalanche.com/node/30408"><span><span><span><strong><span>…;), and a rider was partially buried near Round Lake (</span></span></span></span></span></span><a href="https://youtu.be/cn0lR8XMzl4"><span><span><span><strong><span><u><span>…;).</span></span></span></span></span></span></p>

    <p><span><span><span><span><span><span>This season’s snowpack has been exceptionally weak, and we have seen avalanches every time there is a couple inches of new snow. With the addition of moderate to strong wind today, human-triggered avalanches are likely and natural avalanches are possible. Avoid slopes steeper than 30 degrees and be extra cautious crossing below. The avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>

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