Weather and Avalanche Log for Thu Apr 25, 2024
Temps mid to high 30s overnight. Rain in Bozeman.
Temps mid to high 30s overnight. Rain in Bozeman.
Overnight temps high 20s to mid-30s F.
Elevation: 10231
aspect: ESE
time: 10:35, April 22nd
CTX - broke below isolated block, pit depth ~100cm
Avalanches in the goose lake area: small loose snow avalanches on shady aspects. Evidence of rollerballs and small cornice falls on sunny aspects from previous days.
<p>Warm temperatures, wind-loading, and the possibility of rain and snow later in the week will drive avalanche problems through Friday. As Alex outlined in his <a href="https://www.youtube.com/watch?v=TJm0MFOeqCA&list=PLXu5151nmAvSH326z…; from the Bridger Range, be flexible with your travel plans because conditions can rapidly fluctuate between stability and instability in the spring.</p>
<p>Wet snow avalanches will be the primary concern on most slopes. These will generally occur as wet loose slides that start at a point and spread as they gather snow (<a href="https://www.mtavalanche.com/node/31834"><strong><span>recent examples from the Bridger Range</span></strong></a>). The probability of larger and more destructive wet slab avalanches will increase as nighttime lows remain above freezing and daytime highs climb mid-week. Last week, melt-water moved through the snowpack, and riders in the Taylor Fork (<a href="https://www.mtavalanche.com/node/31856"><strong><span>photos and details</span></strong></a>) and the Northern Gallatin Range (<a href="https://www.mtavalanche.com/node/31874"><strong><span>photos and details</span></strong></a>) remotely triggered wet slab avalanches that broke on weak faceted snow near the ground, and a similar slide broke naturally on Mt. Abundance near Cooke City (<a href="https://www.mtavalanche.com/node/31866"><strong><span>details and photos</span></strong></a>). These were a good reminder that avalanches can still fail deep within the snowpack.</p>
<p>There is a chance of rain on Thursday and Friday. Besides being unpleasant for travel, rain on snow will destabilize the snowpack. Thankfully, identifying wet snow instability is relatively easy. Avoid travel on steep slopes if it is raining (because… yuck!), get on to the snow early in the day when surface-level crusts are supportable and get off before the crust breaks down and more than the upper few inches become slushy and wet. Ensure a safe egress route, as conditions often deteriorate more quickly at lower elevations.</p>
<p>Relatively small dry snow avalanches are possible on upper-elevation slopes that remain shady and cool. This weekend, skiers outside the advisory in the Tobacco Root Mountains triggered a small wind-slab avalanche on a high, north-facing run (<a href="https://www.mtavalanche.com/node/31891"><strong><span>details</span></s…;). Small avalanches in technical or extreme terrain can be deadly if they push backcountry travelers off cliffs or into trees and gullies. If the upper snowpack is dry, dig down and back off steep objectives if you find instability in your tests, observe shooting cracks or indications of fresh wind-loading.</p>
<p><span>Remain diligent with your snowpack assessments and route-finding, and adapt your decision-making to changing conditions.<span> </span></span></p>
On May 2-3, please support the excellent non-profits of Gallatin County, including the Friends of the Avalanche Center (GNFAC Giving Page HERE). Your support goes toward offering free and low-cost avalanche education, weather stations, and avalanche center operations. This season, the education program reached over 5,000 students, including school-age youth and motorized and human-powered users.
Overnight temps in the teens to 20s F
Toured up around bell lake today and after a night of wind, triggered a very small wind slab in a north facing couloir at around 9500-10000ft. It was almost 10” deep and was about 10-15ft across. Snow was being loaded through out the day and was staying cold up high.
Dug a pit around 9700' on a WNW shaded aspect below a couloir on Miller Mountain in Cooke City. We found ~95cm snowpack, with 5-10" of lower-density fresh snow. We dug to the ground and found a consistent and firm snowpack all the way down, didn't find any facets at the ground. Isolated cracking, ECTN25 ~20-25cm down, below the thick melt-freeze crust from the warm-up immediately before this week's snow. The fresh snow had sluffed out on most chutes before we got there (likely during the storm) but we saw very little sluff triggered by our skiing
The fresh snow skied great on shaded aspects that hadn't been affected by wind. Non-shaded snow surfaces were definitely getting wet by 1 pm, the sun felt hot, but we didn't observe any wet slides before we left. The snow on the ride out was very wet, with watery-slush puddles on the lower parts of the trail.