18-19

Natural new snow slab avalanche near Cooke

COOKE CITY
Cooke City
Code
SS-N-R2-D2-S
Elevation
9600
Aspect
N
Latitude
44.97760
Longitude
-110.03000
Notes

Observed on 4/10/19. See photo.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
S - Avalanche released within new snow
Problem Type
New Snow
Slab Thickness
18.0 inches
Vertical Fall
600ft
Slab Width
200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Natural large wet slides at Bridger

Bridger Bowl
Bridger Range
Code
WL-N-R2-D2.5-O
Elevation
8000
Aspect
E
Latitude
45.81410
Longitude
-110.92800
Notes

Evidence seen on Wednesday of large wet slides that likely ran on Monday during heavy rain event. Forecaster observed debris on most steep terrain from Hidden Gully to the Ramp. Debris ran to Goldilocks traverse and the road out of bounds north. Multiple size D2, up to D2.5.

From BBSP email: "Good evidence of wet slide activity across the mtn that prob ran late Monday?
Hidden to the Goldilocks traverse
B Gully past Goldilocks 
Av Gulch/right side? to old lower gulch rd
Colter’s to Reggie’s level
Debris on Z fan at traverse level
Boundary chute to upper gate
Close call to nearly upper traverse."
 

Multiple Avalanches
Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Natural trigger
R size
2
D size
2.5
Bed Surface
O - Old snow
Problem Type
Wet Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Wet and dry slab avalanches Cooke

Mt Republic
Cooke City
Code
WS-N-R2-D2
Elevation
8000
Aspect
N
Latitude
45.00950
Longitude
-109.94900
Notes

 

From e-mail: "some natural, wet slab avalanche activity from yesterday on Mt. Republic.  North facing, 8,000'.  Triggered by wet loose slides from above.

Also, noted one large slab avalanche on the north aspect of Miller Ridge yesterday.  Probably triggered by a cornice fall."

Multiple Avalanches
Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Wet slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Problem Type
Wet Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

GNFAC Avalanche Forecast for Wed Apr 10, 2019

Snowpack and Avalanche Discussion

<p>Since yesterday morning, a potent spring storm dropped 6-12” of heavy dense snow in the mountains across the forecast area. This latest round of moisture pushed three day precipitation totals upwards of 2.5-3” (<strong><a href="https://www.mtavalanche.com/weather/wx-avalanche-log">weather log</a></strong>). On slopes below 8,500’, the new snow has been deposited on a wet and saturated snowpack (<u><strong><a href="https://www.mtavalanche.com/images/19/snowpit-bridger">photo</a></stron…;). The combination of dry snow on the surface and wet snow near the ground will create funky and unpredictable conditions today.</p>

<p>Slides originating in the new snow could gouge into saturated layers deep in the pack, producing large and dangerous avalanches (<strong><a href="https://www.youtube.com/watch?v=foYa455ltOg&amp;list=PLXu5151nmAvRNl9ku…;). Today, use extra caution when traveling on or underneath steep slopes. Avalanches will be easy to trigger, making cautious route finding and conservative decision making essential. &nbsp;</p>

<p>On slopes above 9,000’, wind slabs and storm slabs are the primary concerns. Yesterday, Big Sky Ski Patrol triggered slides on the upper mountain that were big enough to bury a skier or rider. These slides were most prevalent on slopes loaded by westerly winds and stayed confined to the new snow. Skiers outside of Cooke City did not report widespread instability but did find over a foot of new snow which relegated them to low angle terrain choices.</p>

<p>Additional snow and wind today will keep the avalanche danger elevated across the forecast area. Today, don’t become tempted to shoot for your favorite steep lines with all the new snow – keep in mind dangerous avalanche conditions exist. It’s important to note that Bridger Bowl is no longer operating and holds backcountry conditions which means no ski patrol are on duty. If the sun comes out tomorrow, wet snow avalanches will be a growing concern. &nbsp;</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>

Info and Announcements

We will issue weather and snowpack updates on Monday and Friday mornings for most of April, and update our weather log daily.

The Hyalite road is closed to motorized travel until May 16th. Bike and foot traffic is allowed.