On 4/10/23... At lower elevations where the snowpack is shallower, closer to silver gate and the northeast corner of the park, there were some deeper wet loose slides (D2) and a couple small wet slabs (photo). I would estimate most of these happened yesterday (4/10).
We rode up to Lulu pass, around the back of Fisher Mtn, behind Crown Butte and out Miller Creek south of Crown Butte/Daisy Pass. The upper snowpack was wet, but supportable. We dug down about 3 feet in a meadow in Miller Creek. HS 255cm. The snowpack was wet in the top 20 cm. -1.5degree C down 20cm and -3C down 60 cm. Still dry 40 cm below surface.
Wind was strong out of the southwest. Skies became mostly cloudy around midday, but seemed to clear slightly in the afternoon. Temperatures in the high 30s to mid-40sF.
There were maybe 6-10 D1.5-D2 wet loose slides scattered around the area that we could see, similar to attached picture of Crown Butte (We could see Miller Mtn. east and north, Scotch Bonnet, Henderson, Crown Butte, Abundance, Wolverine). At lower elevations where the snowpack is shallower, closer to silver gate and the northeast corner of the park, there were some deeper wet loose slides (D2) and a couple small wet slabs (photo). I would estimate most of these happened yesterday (4/10). Today, a D1.5 wet slide buried one lane of road in YNP on a steep, treed ENE facing slope at 6900'.
A skier at Big Sky Resort saw three new wet snow avalanches on 4/10. Photo: J Aid
A skier at Big Sky Resort saw three new wet snow avalanches on 4/10.
<p>Very dangerous conditions for wet snow avalanches exist across the advisory area, without freezing temperatures for 48 hours in all but the highest elevations. Slides will entrain wet surface snow, endangering humans in their path, or break out as large slabs of flowing concrete-like snow that could level sections of forest. They may run long distances, crossing groomed roads, ski runs (this one’s for you, Bridger Bowl tourers), and even highways below steep snow-covered terrain (<a href="https://www.mtavalanche.com/node/29022"><strong><span>photos and details</span></strong></a>). Yesterday, a pilot flying over the area noted, “Too many point releases (wet loose avalanches) to count in every range I’ve crossed” (<a href="https://www.mtavalanche.com/node/29045"><strong><span>observation and photos</span></strong></a>). Alex saw five natural avalanches large enough to bury or injure a person and many smaller slides in the Bridger Range (<a href="https://www.mtavalanche.com/node/29060"><strong><span>details</span></s…;). The Big Sky Ski Patrol closed terrain to manage the danger and saw full-depth, wet loose snow avalanches on aspects that face the sun (<a href="https://www.mtavalanche.com/node/29052"><strong><span>details</span></s…;).</p>
<p>The warm-up is weakening cornices and sending blue whale-sized blocks tumbling downhill. We received an aerial photo of a new cornice collapse in the Northern Madison Range (<a href="https://www.mtavalanche.com/node/29050"><strong><span>photo and details</span></strong></a>). On Sunday, a backcountry skier near Big Sky Resort had a close call when they triggered a cornice that, in turn, triggered a deep avalanche on the slope below (<a href="https://www.mtavalanche.com/node/29042"><strong><span>details</span></s…;).</p>
<p>Keep wintery avalanche problems like wind slabs and persistent weak layers in mind, especially with a snowstorm forecast to start tomorrow. Last week’s storm brought large avalanches breaking on persistent weak layers to the <a href="https://www.mtavalanche.com/node/29012"><strong><span>Northern Madison Range</span></strong></a>, <a href="https://www.mtavalanche.com/node/29004"><strong><span>Southern Gallatin Range</span></strong></a>, <a href="https://www.mtavalanche.com/node/28949"><strong><span>Lionhead Area</span></strong></a> and <a href="https://www.mtavalanche.com/node/28900"><strong><span>Bridger Range</span></strong></a>.</p>
<p>The danger from wet snow avalanches starts the day as CONSIDERABLE and will increase to HIGH. Traveling on or below steep slopes is not recommended.</p>
<p>With slightly cooler temperatures, the mountains around Cooke City are a day behind those elsewhere in the advisory area. Temperatures remained above freezing last night, and riders observed many small, wet loose snow avalanches and a large cornice fall near Mount Abundance (<a href="https://www.mtavalanche.com/node/29059"><strong><span>photos</span></st…;). Anticipate larger avalanches today, giving yourself a wider margin below steep sun-soaked slopes, as slides could run into the flats.</p>
<p>Wintery avalanche problems are not done for the season. Recent slides involving wind slabs occurred as recently as last Thursday, and deeply buried weak layers produced avalanches a week ago (<a href="https://www.mtavalanche.com/node/28986"><strong><span>skier-triggered wind-slab</span></strong></a>, <a href="https://www.mtavalanche.com/node/28994"><strong><span>Natural Wind-slab 1</span></strong></a><strong>, </strong><a href="https://www.mtavalanche.com/node/29005"><strong><span>Natural Wind-slab 2</span></strong></a>, <a href="https://www.mtavalanche.com/images/23/huge-deep-slab-mt-abundance"><str… slab Mt. Abundance</span></strong></a>, <a href="https://www.mtavalanche.com/node/28924"><strong><span>Deep slab Woody Ridge</span></strong></a>). Tomorrow, cooler temperatures and snow return, and these problems will return to the forefront.</p>
<p>The avalanche danger is CONSIDERABLE due to the wide array of avalanche concerns, including increasing wet snow danger throughout the day.</p>
<p>Please continue to share avalanche, snowpack or weather observations via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Drove Bridger Canyon to Seitz road around 5pm on 4/10. Saw 4-5 D2 wet loose, plus many D1 wet loose. No huge slides or widespread large wet activity, yet.
Riders near Cooke City saw a couple of cornice falls that triggered the snow below on 4/10
A large cornice collapse on Mount Abundance triggered an avalanche on the slope below. Photo: A Mulkey
A small cornice fall near Cooke City and pinwheels from a rocky face. Photo: A. Mulkey
