20-21

Third Yellow Mule / Skier triggered slide + remote

Date
Activity
Skiing

Sled Skiing in Third Yellow mule... after an air onto the slope the impact from landing resulted in a fracture and failure to / near the ground... in addition, a remote trigger occurred on adjacent slope... 200-300 ft to the skiers right. No body was caught in either slide. Skier that initiated failure was moving at high speed and was beyond slide path before majority of snow movement began.

2 pits where dug prior to riding terrain. One on adjacent slope, we went through to ECT 30 and continued to hammer on the column through 40 wacks of double fist, full force before failure occurred 30 cm above ground. Second pit was dug on slope where slide was initiated... same results, very hard to get failure to occur. Snowpack depth varied from 125 - 180 cm in the area... our pits were dug in depths of around 125 cm and 170 cm respectively.

Region
Northern Madison
Location (from list)
Buck Ridge
Observer Name
Wiley Miller

From obs (2/28/21): "I’ve attached a photo of a small, D1.5, slide I saw on a thin S facing slope at 9000’. It was definitely more than a few days old. HS in the areas you would want to ski is 130-180cm, with a distinct drop felt with a probe at the bottom of the pack. Other areas are very scoured up there." S. Jonas

Avalanche Details: Small natural near Fawn Pass
Southern Gallatin, 2021-03-01

Taylor Fork

Date
Activity
Snowmobiling

With recent persistent winds the cornices are growing to impressive size. Noted a few natural cornice drops on the south 'rim' of Sage Basin.

Region
Southern Madison
Location (from list)
Taylor Fork
Observer Name
Robb Larson

GNFAC Avalanche Forecast for Mon Mar 1, 2021

Snowpack and Avalanche Discussion

<p>Welcome to March. We have an abrupt transition to the new month as we begin talking about wet snow avalanches after a February of record snowfall. Today, temperatures near freezing (thawing)&nbsp;and sunny skies will be a shock to the cold snowpack. Recent soft snow will begin to melt, lose strength and slide naturally on steep slopes. Slopes that get direct sun will be the first to have loose snow avalanches this morning. Anywhere you feel moist or wet snow on the surface is a sign similar slopes are becoming unstable.</p>

<p>Loose snow avalanches are likely today. These could run long distances and become large as they entrain recent snow. Additionally, February’s snow and wind created massive cornices along ridgelines that will break naturally and be easy to trigger. Cornice falls and loose snow slides will likely trigger larger slabs of recent snow, or possibly step down and trigger a very large deep slab on weak sugary snow near the ground (<a href="https://www.mtavalanche.com/images/21/mt-ellis-weak-snow-ground"><stron…;, <strong>videos from </strong><a href="https://youtu.be/Ychm42ihtjk"><strong>Blackmore</strong></a&gt; and <a href="https://youtu.be/65JO-4w4qXo"><strong>McAtee Basin</strong></a>).</p>

<p>Yesterday near Cabin Creek a snowbiker triggered a large avalanche that broke 3 feet deep on weak snow (<strong><a href="https://www.mtavalanche.com/node/24472">details and photos</a></strong>). Doug and I skied north of Bridger Bowl and found 1-2 foot thick wind slabs that cracked under our skis, and we dug down to see the soft, weak sugary snow buried six feet deep (<strong><a href="https://www.mtavalanche.com/images/21/cracking-wind-slabs">photo</a></s…;, <strong><a href="https://www.youtube.com/watch?v=d_BOYcpqP-I&amp;list=PLXu5151nmAvQDzKmH…;). Dave saw the same poor, untrustworthy snowpack structure in Taylor Fork (<strong><a href="https://www.youtube.com/watch?v=d_BOYcpqP-I&amp;list=PLXu5151nmAvQDzKmH…;). Near Cooke City the weak snow near the ground is less widespread, but some recent avalanche activity has shown weaker snow exists on some slopes with a relatively shallower snowpack (<a href="https://www.mtavalanche.com/node/24432"><strong>details</strong></a&gt; of a natural avalanche in Hayden Creek earlier in the week). Keep these wind slabs and deep slabs in mind, they are possible to trigger even where the snow remains cold and dry today.</p>

<p>Today warm temperatures and sunshine will be an unwelcome change for the cold snowpack. Large to very large natural avalanches are possible, and skier and rider triggered avalanches are likely on steep, sunny slopes. Avoid travel on and underneath large cornices and steep slopes where the snow is becoming wet from the sun or warm temperatures. The avalanche danger is rated CONSIDERABLE.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

The Beacon Park at Beall Park in Bozeman is running!

The Friends of the Avalanche Center in partnership with the City of Bozeman put in a Beacon Park at Beall Park. It is located on the north side of the Beall building between N. Bozeman Ave. and the ice rink. Stop by with your

Snowbike triggered avalanche, Red Canyon near W. yellowstone

Cabin Creek
Southern Madison
Code
HS-AMu-R4-D2-O
Latitude
44.89490
Longitude
-111.22800
Notes

Riders triggered this slide on 2/28/21 near Red Canyon/Cabin Creek, north of West Yellowstone. Nobody caught or injured, but close call.

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
4
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year