24-25

<p><span><span><span><span><span><span>Today’s primary avalanche problem is human-triggered </span></span></span></span></span></span><span><span><span><strong><span><span>persistent slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> breaking on weak layers that formed in late January. Over the previous 12 days we received reports of multiple persistent slab avalanches, breaking 2-3 feet deep and 50-200 feet wide. The most recent, that we know of, were triggered by snowmobilers on Friday at Lionhead (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34421"><span><span><span><span><span><… and observation</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>). One slide broke 5 feet deep on a heavily wind-loaded slope (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=TWCNOrvNvLk&amp;embeds_referring_euri=h…;). Many recent avalanches were close calls with riders narrowly avoiding being caught and some partially buried and dug out by partners (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34413"><span><span><span><span><span><… in Cabin Creek</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34368"><span><span><span><span><span><… Monday in Cooke</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, last weekend in </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34341"><span><span><span><span><span><… Basin 1</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34301"><span><span><span><span><span><… Basin 2</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34367"><span><span><span><span><span><… City</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34327"><span><span><span><span><span><… Fork</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, and </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=tAiSHSEDJhY"><span><span><span><span><s… two Wednesdays ago</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>).&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>During our visits to Lionhead on Friday and the southern Madison Range on Saturday (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34438"><span><span><span><span><span><…;) we dug down and found the weak layers creating a poor structure in our snowpits. Although the weak layers were stubborn and did not produce many unstable test results, the recent avalanche activity is evidence to be cautious of steep slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The problem is tricky because unstable slopes are not widespread, and many (not all) recent slides have been on mid-elevation slopes, surrounded by trees and sheltered from the wind. These may be less typical places you would consider avalanches. Your best options are either avoid slopes steeper than 30 degrees, or before committing to steep slopes dig down 3-4 feet to check for buried weak layers, and choose slopes with minimal consequences such as gullies, trees or cliffs (</span></span></span></span></span></span><a href="https://youtu.be/W_BeKTJQbUc?feature=shared"><span><span><span><span><s… from Saturday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>).&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is MODERATE near West Yellowstone and Cooke City.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near Bozeman, Big Sky and Island Park avalanches are unlikely. Cooler temperatures and cloudy skies will end the threat of wet snow avalanches that were the main concern over the weekend. Additionally, we have not seen deeper persistent slab avalanches like we have in other areas, and drifts that formed last week should be glued on.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>A couple things to keep in mind are large cornices along ridgelines and small drifts that might form with new snow and light to moderate wind later today.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>On Saturday skiers in Hyalite noted cornices peeling off the ridgeline and a cornice fall that triggered a wind slab avalanche (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34440"><span><span><span><span><span><…;). Cooler temperatures should prevent cornices from breaking naturally today, but some may be teetering on edge after the recent above freezing temperatures. Stay far back from the edge of cornices if you travel along ridgelines.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>If snow starts early or piles up quickly some small fresh drifts might form late this afternoon. These should be generally harmless, but a small wind slab avalanche could knock you over. Be careful of fresh drifts on steep slopes where a small slide could carry you a long distance or push you over cliffs or into trees.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is LOW near Bozeman, Big Sky and Island Park.</span></span></span></span></span></span></p>