Heavy, wet slide of recent snow released while skiing off South Saddle. Photo is from South Central.
Winter conditions in middle basin. Cracking in wind drifted pockets at the top of bat ears couloir and at the top of middle peak. Snowing hard all afternoon nearly filling in our skin track by the time we exited.
Toured around Beehive and Middle Basins this morning, finding predictably bulletproof snow on most aspects but decent turns aided by the 2-4 inches of snow from last night on northerly terrain that hadn’t been destroyed by the sun this week. There were a few brief moments of direct sun throughout the morning, which almost instantaneously triggered point releases from steeper rocky terrain. On the way back through Beehive we observed some much larger debris piles that weren’t there this morning from the steel rocky face between the Going Home chute and the prayer flags.
Skied the north chutes above fairy lake around 8,400 ft. Found 8-12" of new snow, with the bottom 2" consisting of large graupel. In steep terrain our sluff entrained lots of snow making for some large debris piles. Overall the snow was generally well bonded.
Skied Hellroaring Hut in the Centennials from Friday Mar 28 through Mon Mar 31.
Skied and observed all aspects between 7700' and 10,200' in the vicinity of Mt Jefferson and Reas Peak.
We had good visibility for three days and saw no signs of slab avalanches; no whumphing or cracking; and no signs of blowing or drifting snow (prior to new snow arriving today (Mar 31) snow surface was locked up with solid melt-freeze crusts on all aspects and elevations).
Snow surface starting to show meltwater runnels on S through E aspects below 9000'.
Test pits on N and S aspects at 9100' revealed moist snow under melt-freeze crusts (3" thick breakable crust on N aspects; 10" thick stout crust on S aspects) and no identifiable layers of concern in the upper 130 cm of the snowpack. HS 165 cm on S aspect at 9100' and HS 260 cm on N aspect at 9100'.
We observed pinwheels and predictable wet loose avalanches (D1 to D1.5) on solar aspects above 8000' on Fri and Sat.
Snow started this morning (3/31) and 2.5" of new snow had accumulated when we left at 11:00 a.m. Moderate to strong winds blowing from the south today.
Shooting cracks in wind drifted snow on the northwest side of Miller Ridge, and wet loose slides on the southeast side. Very variable out there.
<p><span><span><span><span><span><span>Near Bozeman, Big Sky and Cooke City, 9-15” of snow (0.7-1.3” snow water equivalent) fell since Friday and creates the main avalanche problems today. Near Island Park has received 2-3” with heavy snow possible today which will form similar hazards.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>This morning the wind increased out of the southwest and is drifting new snow into thicker slabs which makes </span></span></span></span></span></span><span><span><span><strong><span><span>wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> possible for people to trigger. Yesterday the wind was calm and the snow was mostly unaffected (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=o6qkMwPpVeg&list=PLXu5151nmAvToI_ir… from Mt. Blackmore</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>), so today there is plenty of snow to grow large, fresh slabs which might be easy to trigger. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Additionally, </span></span></span></span></span></span><span><span><span><strong><span><span>dry loose or wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> can slide easily on firm melt-freeze crusts buried below the new snow. Any sunshine or above freezing temperatures will quickly make the new snow wet and more cohesive, and increase the chances of larger loose snow slides or </span></span></span></span></span></span><span><span><span><strong><span><span>storm slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> on non-wind-loaded slopes. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Yesterday skiers in the Bridger Range triggered small wind slabs (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34793"><span><span><span><strong><span…;) and loose snow avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34797"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/25/sluff-debris-pile"><span><span><s…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Assess the stability of the new snow as you travel and watch for changing conditions throughout the day. Be cautious of steep slopes with fresh drifts or a moist snow surface. Cracking across the snow surface is a sign fresh drifts are unstable, and roller-balls or pinwheels indicate a moist snow surface and increasing potential for wet loose slides. Avalanches might not be huge, but even small slides can be harmful if they knock you over a cliff or drag you into trees or rocks. Before riding steep slopes consider the consequences of being caught in any size slide.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Avalanche danger is MODERATE near Bozeman, Big Sky, Cooke City and Island Park.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Near West Yellowstone, 1-3” of snow fell since Friday with a few inches possible today. Small </span></span></span></span></span></span><span><span><span><strong><span><span>wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> can be triggered where the new snow is drifted into fresh slabs today. Watch for snow blowing across ridgelines, or cracking across the snow surface as signs that fresh drifts exist. Small </span></span></span></span></span></span><span><span><span><strong><span><span>wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> are also possible if the new snow warms up and gets wet. These problems are mainly only an issue where a small slide knocking you off your feet would have high consequences, such as above cliffs or on long, steep slopes.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Aside from small instabilities involving the new snow, the snowpack is generally stable, and large avalanches are unlikely. The avalanche danger is LOW near West Yellowstone.</span></span></span></span></span></span></p>
Starting tonight Hyalite road will be closed to ALL MOTORIZED VEHICLES until the morning of May 16. This is a regular annual road closure to reduce road damage during the spring thaw. Bicycle and foot traffic are allowed. Contact the Bozeman FS Ranger District for more info.
"Skied the north chutes above fairy lake around 8,400 ft. Found 8-12" of new snow, with the bottom 2" consisting of large graupel. In steep terrain our sluff entrained lots of snow making for some large debris piles. Overall the snow was generally well bonded." Photo: S. Lipsteuer
Skied the north chutes above fairy lake around 8,400 ft. Found 8-12" of new snow, with the bottom 2" consisting of large graupel. In steep terrain our sluff entrained lots of snow making for some large debris piles. Overall the snow was generally well bonded.
