23-24

<p><span><span><span><span><em><u><span><span>Avalanche Accident near Mt. Blackmore</span></span></u></em></span></span></span></span></p>

<p><span><span><span><span><em><span>Two skiers were ascending a northeast-facing</span></em></span></span></span></span><a href="https://www.mtavalanche.com/taxonomy/term/259"><span><span><span><span>…; avalanche path</span></em></span></span></span></span></a><span><span><span><span><em><span> on the northernmost ridgeline of Mount Blackmore around 1 p.m. when they triggered a large, dry</span></em></span></span></span></span><a href="https://www.mtavalanche.com/taxonomy/term/304"><span><span><span><span>…; slab</span></em></span></span></span></span></a><span><span><span><span><em><span> avalanche that failed 3 feet deep, 150 feet wide, and ran 500 feet vertical. Debris piled up 4-8 feet deep. The avalanche failed on weak,</span></em></span></span></span></span><a href="https://www.mtavalanche.com/taxonomy/term/277"><span><span><span><span>…; faceted snow</span></em></span></span></span></span></a><span><span><span><span><em><span> near the base of the snowpack. One skier was injured and rescued by Gallatin County Search and Rescue. </span></em></span></span></span></span><a href="https://www.mtavalanche.com/node/31526"><span><span><span><strong><em><… and photos are here</span></span></u></em></strong></span></span></span></a><span><span><span><span><em><span>.&nbsp;</span></em></span></span></span></span></p>

<p><span><span><span><span><span><span>As evidenced by this accident yesterday and avalanche activity over the season (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><span><span><span… log</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>), weak snow at the bottom of the snowpack is still a problem. Although the frequency at which avalanches are occurring is decreasing, the consequences of getting caught are not. Yesterday Ian and I went to Saddle Peak in the Bridger Range and found a poor snow structure which was </span></span></span></span></span></span><span><span><span><span><span><u><span><span>similar to the rest of our forecast area</span></span></u></span></span></span></span></span><span><span><span><span><span><span>: weak snow underlying the winter’s snowfall. The interface between the weak, sugary facets and slabby snow is noticed by digging with your shovel. The airy bottom layer can’t be missed.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Temperatures are going to warm and melt the snow surface, and at low elevations glop up the entire snowpack. Wet loose avalanches may travel long distances and could even trigger deep and big </span></span></span></span></span></span><span><span><span><span><em><span>dry</span></em></span></span></span></span><span><span><span><span><span><span> avalanches. Avalanches breaking deep are likely to be triggered 3 ways: from additional loading (snowfall or debris from wet, loose avalanches), from melt-water percolating down to the weak layer, or by triggering from a thinner spot, like the skiers near Mt. Blackmore did. My </span></span></span></span></span></span><a href="https://youtube.com/shorts/PyHc_9gjFWA"><span><span><span><strong><span… from Saddle Peak</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> shows this layer and discusses these points.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The danger will rise as the snow surface melts. Conditions will change rapidly, both temporally (in as little as 15 minutes) and spatially (soft skiing up high gives way to crashing through the wet snow lower on the slope). We have weak and unstable snow which is buried deep on many places. This depth makes it more difficult to trigger and more dangerous to be caught. Today, head home as the snow gets soft and punchy, and if you are on a shady aspect beware of hitting a thin spot that could trigger the entire slope. Dave’s recent </span></span></span></span></span></span><a href="https://youtu.be/Eb7HWFq7A0Q"><span><span><span><strong><span><u><span>… from Beehive Basin</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> is instructive for wet snow avalanches.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The danger will start out as MODERATE and rise to CONSIDERABLE as the snow surface wets.</span></span></span></span></span></span></p>