19-20

We triggered this avalanche of wind-drifted snow as we approached very carefully from a low angle slope above, on 1/30/2020. Triggered from where Alex is standing. Near Lulu Pass outside Cooke City on a south facing slope at 10,000'. It broke within recently drifted snow, but these slabs could be enough weight to break deeper and wider on sugary layers deep in the snowpack. Photo: L. Browning

Cooke City, 2020-01-30

We triggered an avalanche of wind-drifted snow as we approached very carefully from a low angle slope above, on 1/30/2020. It broke within recently drifted snow, but these slides could be enough weight to break deeper and wider on sugary layers deep in the snowpack. Photo: GNFAC

Cooke City, 2020-01-30

GNFAC Avalanche Forecast for Thu Jan 30, 2020

Snowpack and Avalanche Discussion

<p>Over the last two days 4-6” has fallen over our forecast area. This is not enough snow to increase the avalanche danger, but is enough to keep us on our toes. We have a weak layer of sugary snow near the ground that continues to exhibit instability. Monday’s large snow storm in the Bridger Range (7” of very dense snow) was enough to trigger a 5-10’ deep avalanche on Naya Nuki Peak (<strong><a href="https://www.mtavalanche.com/images/20/avalanche-naya-nuki">photo</a></s…;). Since then, natural avalanches have not been seen, but stability tests are breaking on this layer, a warning that human-triggered avalanches are not out of the question. On Tuesday, Ian and I saw this in Beehive Basin (<strong><a href="https://www.mtavalanche.com/images/20/beehive-basin-still-showing-some-…;, <strong><a href="https://youtu.be/Zu3Ckyt7qj4">video</a></strong&gt;), Dave had the same on Buck Ridge (<strong><a href="https://youtu.be/rhyqSqB4w8c">video</a></strong&gt;), and sledders and skiers in Taylor Fork and Hyalite also got this layer to release in their tests.</p>

<p>The Lionhead area and the mountains around Cooke City have been quiet with no recent avalanche activity, cracking or collapsing. However, the weak layer of sugary facets is buried deep in these mountains and still breaking in tests last weekend in Cooke City. These results gives me slight pause even though the stability trend is positive.</p>

<p>In the absence of visual clues that slopes are unstable (avalanches or “whumphs”) we rely on digging to get the information we need. If you are heading onto a steep slope perform a stability test as one last step in your assessment before committing. I’m a fan of the <strong><a href="https://youtu.be/6s9LND3-gho">Extended Column Test</a></strong>. If the column breaks clean, at the very least it will instigate a robust discussion with your partners, and might even change your plans.</p>

<p>For today, avalanches are still possible and the danger is rated MODERATE. Additionally, wet, loose snow avalanches might sluff off steep slopes getting baked by the sun.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an&nbsp;<u><strong><a href="https://www.mtavalanche.com/node/add/snow_observation">observation form</a></strong></u>, email us (<u><strong><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></strong></u&gt;), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>

King and Queen of the Ridge at Bridger Bowl

This Saturday, February 1, is the King and Queen of the Ridge at Bridger Bowl! Come up and help us raise money by hiking and skiing laps on the ridge. Prizes, camaraderie and a good time are guaranteed. Register with Bridger to hike in the event and create a pledge page to raise funds with your Ridge laps.

Natural Avalanche on Naya Nuki

Naya Nuki Bowl
Bridger Range
Code
HS-N-R2-D2.5-O
Latitude
45.88830
Longitude
-110.95900
Notes

Avalanche crown visible near the top of Naya Nuki Peak in the Northern Bridgers. Estimated max crown depth of 10 ft, approximately 200 ft wide. Photo taken Jan 29th, 2020. Several inches of snow were on the debris, avalanche likely occurred on Monday, Jan 27th. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
2
D size
2.5
Bed Surface
O - Old snow
Slab Thickness
100.0 inches
Slab Width
200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Avalanche crown visible near the top of Naya Nuki Peak in the Northern Bridgers. Estimated max crown depth of 10 ft, approximately 200 ft wide. Photo taken Jan 29th, 2020. Several inches of snow were on the debris, avalanche likely occurred on Monday, Jan 27th. Photo: E. Otto

Bridger Range, 2020-01-29

Small Wind Slab on Mt. Blackmore

Mt Blackmore
Northern Gallatin
Code
SS-AS-R1-D1-I
Elevation
9200
Latitude
45.44390
Longitude
-110.99700
Notes

Snow picked up at Mt. Blackmore with calm to light winds. Someone up there before us pulled out a small wind loaded pocket on the face leaving the basin.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
R size
1
D size
1
Bed Surface
I - Interface between new and old snow
Slab Thickness
6.0 inches
Vertical Fall
50ft
Slab Width
20.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

GNFAC Avalanche Forecast for Wed Jan 29, 2020

Snowpack and Avalanche Discussion

<p>In the last 24 hours, the mountains from Big Sky through West Yellowstone received 4-6” of snow equal to 0.3-0.4” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE). Other ranges received 1-3” (0.1-0.3” of SWE). The added weight of the new snow on a weak snowpack warrants extra caution if you are considering entering avalanche terrain today. Avalanches within the new snow are the most likely problem. These will be most concerning in high consequence terrain where a small avalanche could be dangerous. Less likely, but more frightening are large avalanches that could break on weak snow deep in the snowpack and fail over a wide area.</p>

<p>Doug and Ian collected field data in Beehive Basin yesterday and found the sugary snow near the bottom of the snowpack was still weak and able to produce an avalanche (<a href="https://www.mtavalanche.com/images/20/beehive-basin-still-showing-some-…;, <strong><a href="https://www.youtube.com/watch?v=Zu3Ckyt7qj4&amp;list=PLXu5151nmAvSbcbVf…;). I dug a snowpit yesterday in Second Yellowmule and found that while it is becoming more difficult to trigger an avalanche, the potential for a giant slide is still real for an unlucky skier or rider (<a href="https://www.mtavalanche.com/images/20/2nd-yellowmule-profile-28-jan-202…;, <a href="https://www.youtube.com/watch?v=rhyqSqB4w8c"><strong>video</strong></a&…;). My pit was close to the <strong><a href="https://www.mtavalanche.com/node/21453">massive avalanche</a></strong> that broke three weeks ago, snow and wind have nearly erased the evidence that the slide ever occurred, in its place are enormous cornices that could break far back from the edge (<a href="https://www.mtavalanche.com/images/20/massive-cornices-buck-ridge-28-ja…;). One skier north of Bridger Bowl was surprised yesterday with numerous unstable extended column tests propagating failure when before the storm, his tests showed stable results. The information we gathered in the Northern Madison Range yesterday corresponds to what we have seen across our advisory area. Go to our <strong><a href="https://www.youtube.com/playlist?list=PLXu5151nmAvSbcbVfoR785MxkqkNVy8P… page</a></strong> for quick summaries of all the recent data we collected in the field.</p>

<p>We are maintaining a status quo outlook on avalanches, the snowpack, and travel advice. Read the <a href="https://www.mtavalanche.com/blog/2019-2020-mid-season-snowpack-summary-… snowpack summary</strong></a> to catch up on this year’s snowpack and avalanche activity. Today, you can manage the avalanche problems by assessing the snowpack, making conservative terrain choices, exposing only one person at a time to avalanche hazard, and giving cornices a wide berth if you decide to play on or around steep slopes. Human triggered avalanches are possible, and the avalanche danger is rated MODERATE.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an&nbsp;<a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>observat… form</strong></a>, email us (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>

King and Queen of the Ridge at Bridger Bowl

Next Saturday, February 1, is the King and Queen of the Ridge at Bridger Bowl! Come up and help us raise money by hiking and skiing laps on the ridge. Prizes, camaraderie and a good time are guaranteed. Register with Bridger to hike in the event and create a pledge page to raise funds with your Ridge laps.