22-23

Divide & Blackmore slides

Divide Cirque
Northern Gallatin
Code
HS-N-R1-D2-O
Elevation
10000
Aspect
N
Latitude
45.39340
Longitude
-110.96900
Notes

Skiers noted two slides in Divide Basin that occurred on high, steep, north facing slopes lTuesday night when the wind picked up.

Another party noted an avalanche near Blackmore: "We skied the ridge north of Blackmore (Tomahawk Ridge?) traveling between 6800' -9200' on SE-NE aspects. On the ridge above, ~9400' on a NE aspect there was a natural avalanche, maybe cornice failure, probably same timeframe as the Divide slides. ran ~600'. HS-N-D2-R2-O"

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
1
D size
2
Bed Surface
O - Old snow
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

I went for a walk up to divide basin today and noticed two slides that occurred on high, steep, north facing slopes last night (Tuesday night) when the wind picked up 

Northern Gallatin, 2023-03-08

Finding surface hoar 2 feet deep

Date
Activity
Skiing

Dr. Karl Birkeland of the National Avalanche Center skied into Bacon Rind with us today. We found the surface hoar layer that is causing avalanches elsewhere, but in Bacon Rind it is not a serious concern. This is the same layer responsible for deep avalanches in Cooke City and one nearby in Taylor Fork. In this area the weak layer is capped with 4" snow water equivalent (SWE) while in Cooke City it is under 11" of SWE, almost triple the weight. We found no other weak layers of concern.

Region
Southern Madison
Location (from list)
Bacon Rind
Observer Name
Doug Chabot

Divide basin slides

Date
Activity
Snowboarding

I went for a walk up to divide basin today and noticed two slides that occurred on high, steep, north facing slopes last night (Tuesday night) when the wind picked up 

Region
Northern Gallatin
Location (from list)
Divide Cirque

GNFAC Avalanche Forecast for Wed Mar 8, 2023

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Around Cooke City, the Lionhead area, and also in the northern Gallatin Range, we have weak layers buried 3-5 feet deep that are avalanching. On Sunday, </span></span></span></span></span></span><a href="http://www.mtavalanche.com/node/28471"><span><span><span><strong><span>… large avalanche broke on Miller Mountain</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> outside Cooke City with just 3” of new snow…yikes! Yesterday, a 3-foot deep avalanche was </span></span></span></span></span></span><a href="http://www.mtavalanche.com/node/28504"><span><span><span><strong><span>… by a snowmobiler in Lionhead</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>. And last night winds in Hyalite ramped up and are loading slopes, which is on the heels of a 3-5 foot deep skier triggered avalanche on </span></span></span></span></span></span><a href="http://www.mtavalanche.com/node/28436"><span><span><span><strong><span>… Peak that partially buried him on Saturday</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>. As far as the snowpack is concerned, wind-loading is the equivalent of a snowstorm.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Recent avalanches tell us slopes are unstable. Stability tests can be unreliable when our layer of concern is deep. Although the sun is out and fresh powder abounds, we recommend a cautious approach to route-finding and decision-making because </span></span></span></span></span></span><span><span><span><span><em><span>dangerous avalanche conditions exist</span></em></span></span></span></span><span><span><span><span><span><span>. We do not advise getting onto steep slopes in these ranges today.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>In Hyalite, Dave found a new weak layer of sugary facets buried a foot under the surface. Today’s wind-loads could create avalanches on it. We’ll be looking for this layer in other ranges.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Check out </span></span></span></span></span></span><a href="https://youtu.be/42Zk3eLEMvE"><span><span><span><strong><span><u><span>…’s excellent video from Hyalite yesterday</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://youtu.be/llxGMYhmhY0"><span><span><span><strong><span><u><span>…’s drone shots from Lionhead</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, and </span></span></span></span></span></span><a href="https://youtu.be/nZFM_QZxG3Q"><span><span><span><strong><span><u><span>… avalanche investigation from Saturday in Cooke City</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>. These 3 videos paint a vivid picture of what we are worried about.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is rated CONSIDERABLE.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>In the Bridger Range, the entire Madison Range and southern Gallatins, we have buried weak layers, but at the moment they are not being loaded. However, instabilities seen on Sunday and Monday point to the need to dig and test slopes we want to play on. On Saturday, night riders triggered a 2-3 foot deep slide on Buck Ridge (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/snowmobiler-triggered-slide-buck-… and details</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). The next day Alex went looking for it and ended up watching cracks shoot away from his sled in the windblown snow (</span></span></span></span></span></span><a href="https://youtu.be/-SJTky6-3wg"><span><span><span><strong><span><u><span>…;). In the Bridger Range on Sunday, skiers triggered small wind slabs (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28482"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>), and on Monday, skiers found small avalanches in the new snow on the Ramp (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28493"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Since the possibility of triggering a slide remains, the avalanche danger is rated MODERATE.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs). </span></span></span></span></span></span><span><span><span><span><span><span>&nbsp;</span></span></span></span></span></span><span><span><span><span><span><span>&nbsp;</span></span></span></span></span></span></p>

<p>Around Cooke City, the Lionhead area, and also in the northern Gallatin Range, we have weak layers buried 3-5 feet deep that are avalanching. Recent avalanches tell us slopes are unstable. Although the sun is out and fresh powder abounds, we recommend a cautious approach to route-finding and decision-making because dangerous avalanche conditions exist. For reference, we would not get onto steep slopes in these ranges today.</p>

Upcoming Avalanche Education and Events

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

Sledder triggered + naturals in LH

Airplane Bowl
Lionhead Range
Code
HS-AMu-R2-D2-O
Elevation
9000
Aspect
E
Latitude
44.72500
Longitude
-111.32200
Notes

We saw 6 natural avalanches on our ride in Lionhead. They all involved snow in the last week or two. On our exit we ran into who a group that witnessed a sledder triggering this slope. It was about 3 feet deep and was clearly wind loaded. Luckily he was not caught. When folks are triggering slides we know other slopes are also unstable. Be careful out there!

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
36.0 inches
Vertical Fall
500ft
Slab Width
100.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year