Avalanche on the SE face of Scotch Bonnet in Tragenic Bowl and one on the NE face of Wolverine. They both broke 2-4’ deep. The avalanche on Wolverine slide aprx 1500’. Both were in wind loaded areas at upper elevations. Photo: BPG
We rode the motorized zone today with Bill and noticed two slides. One on the SE face of Scotch Bonnet in Tragenic Bowl and one on the NE face of Wolverine. They both broke 2-4’ deep. The avalanche on Wolverine slide aprx 1500’. Both were in wind loaded areas at upper elevations. Ski cuts with snowmobiles were not producing avalanches in protected areas.
From FB message. Today (3/19) in Taylor Fork
We went into the Lawnmower in the Deep Creek area. Although Kyle and Haylee had skied in the zone, this was my first time there. For me this was a terrain and snowpack familiarization day. First impressions, that is a scary piece of avalanche terrain and a beautiful area. We skinned up the northwest ridge system and dug two-thirds of the way up and again at the top. In our snowpits, we tried to capture a good picture of multiple elevation bands that encompass the potential starting zones of the run and develop a picture of what we might encounter. Snowpits were 190-265 cm deep and largely resembled what I have seen in the northern Gallatin Range. From my understanding, this is an unusually deep and strong snowpack for the area. The basal facets were the most concerning layer in our 190cm pit (1000' vertical below the top). These were 1 Finger minus to 4 Finger plus hardness and rounding. We just dug to the dirt layer on our upper pit. There was 50-70 cm of settled new snow from this weekend's storm cycle. We got ECTN15 results at the interface below the recent snow (see attached snowpits).
With no signs of instability, a strong snowpack structure, no recent avalanche activity in the visible terrain around us, calm conditions/ no wind-loading, and stable results in our snowpits, we choose to ski the main run. We did discuss that due to the nature of the terrain, each skier would be effectively solo for periods of time because there are limited areas to stop that aren't exposed to the avalanche hazard.
One skier triggered a very small loose snow avalanche that ran 50 vertical feet at the top of the run. Other than that, the descent was uneventful.
Temps at the car when we got back at 3 PM were 37 degrees. With sunny skies, the snow on south and west-facing terrain was getting moist and sticky, but we did not observe any wet snow activity.
We were split boarding south of Cooke City today, up to terrain around 10'000', and finding good snow stability.
Weather was mostly cloudy in the am, partly cloudy in pm. Light winds from the SW.
No fresh avalanche activity observed. Attached is a photo of the only sign of a recent avalanche we could find. (an old crown on an East aspect at 9600').
No collapsing no cracking.
Storm snow: was measuring the HN to be around 50cms at 8500', and 70+cms at 9500'.
With a snowpit attached from a E, NE aspect around 9500'. CTN.
Wind effect: significant in localized places, from the St. Patrick's Day event. Wind drifts were not sensitive where we were traveling.
Location: Mount Maurice
Aspect: N
Elevation: 7,600'
We found a 100cm deep snowpack. In our pit, we got an ECTn13 at 65cm on a melt/freeze crust. We found a layer of facets at the ground that was 5-10cm thick, but we were unable to impact that layer in our tests. We noted other melt freeze crusts and the Feb 4 dirt layer between the new snow on the surface and the layer of facets at the ground.
<p><span><span><span><span><span><span>Snowfall from last Thursday to Monday:</span></span></span></span></span></span></p>
<ul>
<li><span><span><span><span><span><span>West Yellowstone - 37” snow/2.9” water</span></span></span></span></span></span></li>
<li><span><span><span><span><span><span>Island Park - 46” snow/4.8” water</span></span></span></span></span></span></li>
<li><span><span><span><span><span><span>Cooke City - 31” snow/2.9” water</span></span></span></span></span></span></li>
</ul>
<p><span><span><span><span><span><span>This snow was accompanied by strong winds from the west and southwest peaking Sunday night with gusts 65-100 mph. Yesterday winds blew from the north..</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Wind slabs</span></span></strong></span></span></span><span><span><span><span><span><span> or possibly deeper </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> are likely on wind loaded slopes that can easily have double or triple the loading compared to non-wind loaded slopes as my partners and I found </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34670"><span><span><span><span><span><… near Mt. Jefferson</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>. Dave spotted many wind slab avalanches </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34657"><span><span><span><span><span><… Lionhead on Monday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Avalanches are much less likely and the riding conditions will be better on slopes sheltered from the wind where the new snow is well bonded to itself. However, so much new snow has way of exposing weakness in the snowpack (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34599"><span><span><span><span><span><… avalanche in the Taylor Fork</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> is a good example). There are some slopes lurking out there mostly near West Yellowstone and the southern Gallatin and Madison Ranges where the snowpack is relatively shallow and weaker (slopes above Trapper Creek near Hebgen Lake come to mind). </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Today human triggered avalanches are likely to happen on wind loaded slopes where the avalanche danger is CONSIDERABLE. The avalanche danger on non-wind loaded slopes is MODERATE but don’t let your guard down.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The Bridger Range received up to 15 inches of snow Sunday and Monday. Near Big Sky and Hyalite Canyon 14-24 inches of snow has fallen since late last week. Winds from both the south and the north have drifted that snow and formed many </span></span></span></span></span></span><span><span><span><strong><span><span>wind slabs</span></span></strong></span></span></span><span><span><span><span><span><span>.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>As Ian and his partner found </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34666"><span><span><span><span><span><… near the Throne</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, safe travel simply required avoiding recent drifting and riding slopes unaffected by the wind. A group further north </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34665"><span><span><span><span><span><… Frazier basin</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> found wind slabs 1-1.5’ deep that could avalanche. These wind slabs should be gaining strength today, but I’d still avoid them.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Loose wet avalanches </span></span></strong></span></span></span><span><span><span><span><span><span>will happen predictably today as strong spring sunshine quickly warms sunny slopes which will become wet. Most wet avalanche activity usually happens the first time dry powder heats up from sunshine. The greatest threat from loose wet avalanches isn’t necessarily triggering one, but having one rumble down onto you from above. Go to shady slopes without recent drifting for the best snow and riding quality. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Today the avalanche danger is MODERATE with heightened avalanche conditions on wind-loaded slopes and sunny slopes where the snow becomes wet.</span></span></span></span></span></span></p>
