18-19

Cracking and Collapsing up Lick Creek

Lick Creek
Northern Gallatin
Code
Elevation
7600
Aspect
NE
Notes

Skiers got collapses and cracks as they toured up Lick Creek. They reported, "1 large whumph on 26 degree NE terrain @7600’. Investigated and likely weak layer was 3-4 mm facets down 70cm with total HS 105."

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

Skiers got collapses and cracks as they toured up Lick Creek. They reported, "1 large whumph on 26 degree NE terrain @7600’. Investigated and likely weak layer was 3-4 mm facets down 70cm with total HS 105." Photo: Z. Keskinen

Northern Gallatin, 2019-01-23

Small avalanche north of Bridger Bowl

The Ramp
Bridger Range
Code
SS-R2-D1.5-I
Latitude
45.82710
Longitude
-110.93200
Notes

"We noticed this broken slab debris en route to ski the ramp north of Bridger Bowl yesterday.  It was at the ridge line, and the crown was about 18 inches tall. It didn't slide very far, due to its lower angle (<30 degrees) and it is unclear if it slid naturally or from a skier poking over to check it out.  It was located above cliffy, high consequence terrain."

 
Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
R size
2
D size
1.5
Bed Surface
I - Interface between new and old snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

A skier north of Bridger Bowl observed this small avalanche on Tuesday, January 22nd. It's unclear if the side was triggered by a skier or a natural. It appears to only involve new and wind blow snow. Avalanche activity is the number one sign the snowpack is unstable. Photo: M. Murphy

Bridger Range, 2019-01-23

GNFAC Avalanche Forecast for Wed Jan 23, 2019

Snowpack and Avalanche Discussion

<p>Since Friday morning our entire forecast area has received 1.5-2 feet of snowfall (near 2.5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2…; in places). The most accurate measure of instability is avalanche activity and red flags such as collapsing or cracking. Since Friday this list of instability is long and growing with 20 events noted (14 in the northern ranges, 6 in the southern ranges). Check out the <strong><a href="https://www.mtavalanche.com/weather/wx-avalanche-log">Weather and Avalanche Log</a></strong> for a synopsis of snowfall and avalanche activity. &nbsp;</p>
<img alt="Weather and Avalanche Log" data-align="center" data-entity-type="file" data-entity-uuid="40b27aa3-6c04-4079-8f99-5987e94e707e" src="/sites/default/files/inline-images/WxLog.JPG" />
<p>Two avalanches are especially noteworthy:</p>

<ul>
<li>From afar, skiers triggered an avalanche on Wheeler Mountain on Monday (<strong><a href="https://www.mtavalanche.com/node/19777">details</a></strong&gt;). I expect similar instability anywhere there is shallow, faceted snow: Mt. Ellis, Beehive Basin, Bacon Rind, Hebgen Lake and Cooke City to name a few.</li>
<li>Ice climbers triggered a small slide on a popular climb up Hyalite on Monday (<strong><a href="https://www.mtavalanche.com/node/19770">details</a></strong&gt;). Although small, it was extremely dangerous because of the serious terrain. Small avalanches above terrain traps are bad news no matter if you are climbing, skiing or riding. &nbsp;</li>
</ul>

<p>Shallow snowpacks are weak and unstable. Yesterday, Eric found this to be true in Teepee Basin in the southern Madison Range (<strong><a href="https://www.youtube.com/watch?v=ABNKUnYcWIQ&amp;t=0s&amp;list=PLXu5151n…;) and also on a road cut on Hwy 191 (<strong><a href="https://www.mtavalanche.com/images/19/road-cut-avalanche-hwy-191">photo…;). It remains true in the northern Gallatin Range where skiers triggered a 2-foot deep slide on Mt. Wheeler from hundreds of feet away. Having just come back from Cooke City I know it to be true there as well (<strong><a href="https://www.youtube.com/watch?v=orGDvzUtVcw&amp;t=0s&amp;list=PLXu5151n…;). If you sink to ground after stepping off your skis or sled, you can be assured that you found the facets. &nbsp;</p>

<p>Many avalanches are confined to new snow, especially if it has been drifted into wind slabs. This new snow instability is prevalent throughout our advisory area which Alex and Ian found in the Bridger Range on Sunday (<strong><a href="https://www.youtube.com/watch?v=A7iKQ_QWJkY&amp;t=0s&amp;list=PLXu5151n…;). Natural and human triggered avalanches along the <strong><a href="https://www.mtavalanche.com/node/19782">Bridger Ridge</a></strong> (every day since Friday), in <strong><a href="https://www.mtavalanche.com/node/19770">Hyalite</a&gt; </strong>(Monday), in <strong><a href="https://www.mtavalanche.com/node/19790">Beehive Basin</a></strong> (yesterday), near <strong><a href="https://www.mtavalanche.com/node/19794">West Yellowstone</a></strong> (yesterday) and <strong><a href="https://www.mtavalanche.com/node/19773">Cooke City</a></strong> (Monday).</p>

<p>Your homework for today is to remember three points:</p>

<p>1. The avalanche danger will rise as the snow continues to fall.</p>

<p>2. Shallow snowpacks consisting of weak facets should be avoided.</p>

<p>3. New snow will continue to avalanche on steep slopes, especially if it has been drifted by the wind.</p>

<p>For today, the avalanche danger is rated CONSIDERABLE on all slopes and avalanche terrain should be avoided. Collapsing, cracking and recent avalanches are signs of instability and we’ve had all three in the last 24 hours. There will be more today.</p>

<p>If you get out and have any avalanche or snowpack observations to share, contact us via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u&gt;, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u&gt;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Skier killed in avalanche in Colorado

On Monday, a backcountry skier was buried and killed in an avalanche near Aspen, Colorado. Information from the Colorado Avalanche Information Center is HERE.

Snowmobiler triggred slide near Two Top

Two Top
Lionhead Range
Code
SS-AMr-R2-D2-I
Elevation
0
Aspect
N
Notes

From an email:

" ...was riding with a guide group near the Two Top area and remotely triggered this slide as rode past this drainage on the top of the ridge. It was a north facing wind loaded slope in the 38 degree slope range. It broke about 12 inches deep and looked like it was from the last snow/wind loading." 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
2
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Width
12.00ft
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From an email:

"...was riding with a group near the Two Top area and remotely triggered this slide as rode past this drainage on the top of the ridge. It was a north facing wind loaded slope in the 38 degree slope range. It broke about 12 inches deep and looked like it was from the last snow/wind loading." Photo: J. Norlander

Lionhead Range, 2019-01-23

Collapsing at Bacon Rind

Bacon Rind
Southern Madison
Code
Elevation
8200
Notes

From an email: "The snowpack seems to about double by the time you get into the upper meadows. We got one loud whoomph up high around 8200’."

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