22-23

<p><span><span><span><span><span><span>Once again, Cooke City is a catcher’s mitt. A strong storm from the southwest has dropped 17” of new snow (1” of </span></span></span></span></span></span><a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314… water equivalent </span></span></u></span></strong></span></span></span><span><span><span><span><span><u><span><span>or </span></span></u></span></span></span></span></span><span><span><span><strong><span><u><span><span>SWE</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>) with strong south to southwest wind (gusts of 46 mph). More snow and wind will continue to build drifts whose thickness will be measured in feet, not inches. Before this storm is over the snowpack depth could double. Most avalanches happen during a storm and large storms can produce large avalanches. Today is a day to be cautious and stay out of avalanche terrain and away from the flats at the bottom of big slopes (aka. runout zones). For today the avalanche danger is rated CONSIDERABLE but could become HIGH by midday if snowfall intensity and amount are more than expected.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The mountains south of Big Sky to West Yellowstone picked up 3-6” (.3-.5” of </span></span></span></span></span></span><a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314…;). Southwest wind is gusting to 50 mph. Wind blown snow will likely crack and potentially avalanche, especially around West Yellowstone, where Dave found a buried weak layer of feathery surface hoar crystals collapsing under his weight (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/26981"><span><span><span><strong><span… and observation</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Because today’s storm is impacting this weak layer, it’s a good idea to stay clear of avalanche terrain. Natural avalanches are possible on wind-drifted slopes and a skier or sledder could likely trigger a slide, potentially from afar. The danger today will start out as CONSIDERABLE, but may ramp up to HIGH. </span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Big Sky Ski Resort received at least 8” of new snow while the Bridger Range and northern Gallatin Range got 1”. Yesterday ice climbers up Hyalite reported drifting snow at low elevations. Deep drifts were not cracking or collapsing, but at higher elevations in the starting zones a climber or skier could possibly trigger an avalanche (</span></span></span></span></span></span><a href="https://youtu.be/7ZO_rb_eGzs"><span><span><span><strong><span><u><span>… Basin video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Winds blew southwest to west with gusts of 50 mph. Gullies will be loaded with drifts and caution should be used crossing them. Near the ridgetops shooting cracks in wind blown snow are a clear sign of instability. For today, the avalanche danger is rated MODERATE on all slopes.&nbsp;&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>If you get out, please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The Island Park area picked up 3 inches of snow with strong wind. More will fall today. Wind blown snow will likely crack and potentially avalanche, especially if there is a buried weak layer of feathery surface hoar crystals 12-18” under the surface. Because today’s storm is impacting this weak layer, it’s a good idea to stay clear of avalanche terrain. Natural avalanches are possible on wind-drifted slopes and a skier or sledder could likely trigger a slide, potentially from afar.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>There is 1-2” of new snow and more is on the way. Wind is strong with gusts of 40-50 mph at ridgetops, mostly from the southwest. Today, new snow and strong wind will create drifting at all elevations. These thicker slabs of snow could be triggered. Over the weekend skiers released avalanches on wind-loaded slopes in the Bridger Range and in Hyalite (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/avalanche-activity"><span><span><span><stro… activity log</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). At Lionhead on Monday, Dave and his partner triggered 5 loud “whumpfs” which is when a weak layer collapses and propagates (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/26981"><span><span><span><strong><span… and observation</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Think of a whumpf as an avalanche on the flats. This is a red flag warning to avoid avalanche terrain. The collapsing weak layer is feathery crystals of surface hoar buried 1-foot deep and we assume it can be found in nearby ranges.&nbsp;&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Yesterday, Dave and I went into Beehive Basin and found relatively stable conditions (</span></span></span></span></span></span><a href="https://youtu.be/7ZO_rb_eGzs"><span><span><span><strong><span><u><span>…;). Soft snow on the surface will continue to get blown into thicker drifts that could be triggered. Shooting cracks or collapses (whumpfs) in these drifts are signs of instability. I recommend digging down to see what is under your feet or sled. A weak layer of surface hoar or a propagating extended column test should turn you around.&nbsp;&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>For today, the avalanche danger is rated MODERATE since human triggered avalanches are possible. If it snows more than expected in the Lionhead area the avalanche danger will rise to Considerable.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>If you get out, please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today will be snowy in Island Park. Winds are strong and gusting to 50 mph at the ridgetops, mostly from the W-SW, building drifts at all elevations. These thicker slabs of snow could be triggered. Shooting cracks or collapses (whumpfs) in these drifts are signs of instability (</span></span></span></span></span></span><a href="https://youtu.be/PVQkjFvFnnw"><span><span><span><strong><span><u><span>…;). I recommend digging down to see what is under your feet or sled. A weak layer of surface hoar or a propagating extended column test should turn you around.&nbsp;&nbsp;</span></span></span></span></span></span><br />
<span><span><span><strong><span><u><span><span>Request</span></span></u></span></strong></span></span></span><span><span><span><span><span><span>: If you get out riding, let us know if you find a layer of buried surface hoar (feathery crystals) about 1-foot under the surface. If so, beware of steep slopes and runout zones as they could avalanche with more snow or wind-loading. </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>… your observations here</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>. </span></span></span></span></span></span></p>