18-19

Yellow Mountain Wet Slab

Northern Madison
Code
WS-NL-R2-D2.5-G
Elevation
9000
Aspect
S
Latitude
45.29890
Longitude
-111.32000
Notes

Large wet slab avalanche on Yellow Mountain. The slab was most likely triggered by a loose avalanche that released just above the slab. Photos: T. Vanyo

Number of slides
1
Number caught
0
Number buried
0
Number killed
0
Avalanche Type
Wet slab avalanche
Trigger
Avalanche triggered by loose snow avalanche
R size
2
D size
2.5
Bed Surface
G - Ground
Problem Type
Wet Snow
Slab Thickness
24.0 inches
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Two pits on the west side of Saddle peak. They were dug relatively close to each other, but subtle changes in aspect and elevation resulted in very different conditions. North-facing slopes remain cold and dry for now, while anything that is in the sun is transitioning to a springtime snowpack. Photo: GNFAC

Bridger Range, 2019-03-26

GNFAC Avalanche Forecast for Tue Mar 26, 2019

Snowpack and Avalanche Discussion

<p>Avalanches are unlikely this morning, but will become more likely as temperatures rise and crusts break down. Yesterday, skiers triggered loose snow avalanches near Big Sky that while only involving the 3” of new snow, ran 400’ on the firm crust (<strong><a href="https://www.mtavalanche.com/images/19/loose-slides-new-snow">photo</a><…;). Near Cooke City, skiers found the new snow well bonded to the old snow surface. After a day of warm temperatures, this will be the case on most slopes. Still, as the day heats up, you could trigger small loose snow avalanches, particularly in areas that were cloudy yesterday but are sunny today. There may also be isolated pockets where you could trigger a wind slab avalanche. Shady slopes loaded by yesterday’s south and west winds are the most suspect. Be cautious of steep, wind loaded slopes if the snow surface feels stiff and is cracking under your feet or sled.</p>

<p>Yesterday, Doug and I found a dusting of new snow over a stout crust near Lionhead (<strong><a href="https://www.youtube.com/watch?v=C6qgTWYjj7U&amp;list=PLXu5151nmAvRNl9ku…;). On shady slopes the lower snowpack is dry and stable. On sunnier slopes you’ll find unfrozen slush under the crust. As the crust melts this afternoon and becomes unsupportable on those sunny slopes, you could trigger a deeper wet avalanche (<strong><a href="https://www.youtube.com/watch?v=YvYdU9j52zM&amp;index=2&amp;t=0s&amp;li…;). The timing of this breakdown will vary depending on aspect and cloud cover, but once you start sinking above your boot tops in wet snow it’s time to get off steep slopes. Pinwheels and rollerballs are warning signs that the snow surface is becoming wet and the danger is starting to rise.</p>

<p>Avalanche danger is <strong>LOW</strong> this morning and will rise to <strong>MODERATE</strong> this afternoon.</p>

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

Upcoming Avalanche Education and Events

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Long running loose slides in N. Madison

NORTHERN MADISON RANGE
Northern Madison
Code
L-ASc-R1-D1-I
Elevation
11000
Aspect
NW
Notes

From instagram: "Easily triggered 3" soft slabs/loose snow slides. NW facing Northern Madison around 11,000' Ran 400' on sun crust. At least 3 intentionally triggered."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Skier
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
1
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
3.0 inches
Vertical Fall
400ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year