17-18

GNFAC Avalanche Advisory for Sun Dec 10, 2017

Snowpack and Avalanche Discussion

<p>Strong cross-slope winds last week, and strong downslope winds prior to yesterday, drifted snow into slabs in unusual locations in the Bridger Range. Wind slabs one to two feet deep are located below ridgelines and across mid-elevation terrain. Carefully assess terrain for the presence of hard, thick drifts of snow, and avoid these features today. Less wind and limited snow transport yesterday allowed these slabs to gain strength, and they will be difficult to trigger today, but remain possible. Today, avalanche danger is <strong>MODERATE</strong> on wind loaded slopes and <strong>LOW </strong>on all other slopes.</p>

<p><a>A generally stable snowpack exists, and avalanches are unlikely without recent loading from snow and wind. I found these stable conditions in Beehive on Friday (</a><a href="https://www.youtube.com/watch?v=Yyk_tDXoH0w"><strong>video</strong></a&…;), and Doug and Eric had similar findings in Hyalite on Thursday (<a href="https://www.youtube.com/watch?v=RqIx4CG5zrM"><strong>video</strong></a&…;). Watch for isolated wind slabs, and assess terrain for the consequences of being caught in even a small slide.</p>

<p>Small wet loose avalanches were observed during the heat of the day on Friday (<a href="https://www.mtavalanche.com/images/17/small-wet-loose-slides-beehive"><…;, <a href="https://www.mtavalanche.com/images/17/wet-loose-cooke-city"><strong>pho…;), and are possible today. Sunny slopes will have a firm crust on the surface this morning, which will inhibit wet avalanche activity. If this crust softens, be cautious of small wet loose slides on sunny slopes this afternoon.</p>

<p>Conditions are generally stable, but it is important to continue safe travel habits. Expose no more than one person at a time to avalanche terrain. Practice clear communication and identifying safe zones. Take time to practice with your rescue gear.</p>

<p>Today, a generally stable snowpack without recent snow or wind-loading makes avalanche danger <strong>LOW</strong>.</p>

<p>If you get out and have any avalanche or snowpack observations to share, drop a line 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

Events and Education Calendar

BILLINGS

Dec. 12, Avalanche Awareness for Snowmobilers, 6-7:30 p.m. at Red Lion Hotel and Convention Center, Billings

BOZEMAN

Dec. 13, Avalanche Awareness, 6:30-8 p.m. at Gallatin Valley Snowmobile Association, 4-Corners

Dec. 21, Avalanche Awareness, 6-7:30 P.m. at Play It Again Sports, Bozeman

GNFAC Avalanche Advisory for Sat Dec 9, 2017

Snowpack and Avalanche Discussion

<p>Strong downslope winds continue to produce unusual loading patterns in the Bridge Range. Yesterday, the Bridger Bowl Ski Patrol closed sections of the Ridge due to heavy wind loading in mid-elevation terrain. Today, snow transport should be limited, but slabs that formed over the past few days will be scattered throughout the range. These slabs should be stiff and stubborn, but they could still fail under the weight of a skier or rider. Watch for and avoid thick wind drifts on the leeward side of ridgelines, gullies and cross loaded terrain features.</p>

<p>Today, heightened avalanche conditions exist on wind loaded slopes which have a <strong>MODERATE</strong> avalanche danger. Non-wind loaded slopes have a <strong>LOW</strong> avalanche danger.</p>

<p><a>Today, there isn’t much new to report. Without a recent loading event, our generally stable snowpack remains in good shape. Yesterday, Alex ventured into Beehive Basin near Big Sky and found stable snow in his snowpits (</a><a href="https://www.youtube.com/watch?v=Yyk_tDXoH0w"><strong>video</strong></a&…;). He did observe a few wet loose slides on south facing slopes, but these were small and posed little threat. This is consistent with observations from Hyalite and the Cooke City area (<a href="https://www.mtavalanche.com/images/17/small-wet-loose-slides-beehive"><…;, <a href="https://www.mtavalanche.com/images/17/wet-loose-cooke-city"><strong>pho…;, <a href="https://www.youtube.com/watch?v=RqIx4CG5zrM"><strong>video</strong></a>…;

<p>Aside from small wet loose slides and isolated wind slabs, there isn’t much in the way of avalanche hazard. Although conditions are generally stable, now is no time to become complacent. It’s important to remember that avalanches can still happen and even small slides can have severe consequences.</p>

<p>Today, a stable snowpack combined with stable weather will create generally safe avalanche conditions. For this reason the avalanche danger is rated <strong>LOW</strong>.</p>

<p>If you get out and have any avalanche or snowpack observations to share, drop a line 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

Events and Education Calendar

BOZEMAN

Dec. 13, Avalanche Awareness, 6:30-8 p.m. at Gallatin Valley Snowmobile Association, 4-Corners

Jan. 12 and 13, Companion Rescue Clinic, Info and Register

Small wet loose slides were observed on sunny aspects outside of Cooke City. These slides weren't big, but they're an indicator that instability with sunny skies and above freezing temps. Photo: B. Fredlund 

Cooke City, 2017-12-09