From text message: “I was out with a friend and his 2 daughters. We were east of Jefferson 8990’ elevation. East aspect ECTP 22. Down 78cm from surface. Melt freeze layer I would describe as breaking up?? garbage.”
<p><span><span><span><span><span><span>Around West Yellowstone, Island Park and Cooke City, 3-4” of new snow yesterday along with strong gusty winds built touchy wind slabs that will be easily triggered today. Riders in Island Park yesterday reported heavy snowfall, strong winds, and touchy wind slabs and cornices (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34706"><span><span><span><span><span><…;). </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>are most likely to break in the newly formed drifts, but could also break into deeper drifts from the multiple feet of snow that fell last weekend. These drifts are mostly at upper elevations, below ridgelines and cornices.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>In addition to wind drifts, near West Yellowstone, you could also trigger a slide on deeper persistent weak layers. You aren’t super likely to trigger a </span></span></span></span></span></span><span><span><span><strong><span><span>Persistent Slab avalanche </span></span></strong></span></span></span><span><span><span><span><span><span>today as we’ve only had two reports of these slides in the last three weeks. But, the snowmobile triggered slide in the Taylor Fork on Wednesday shows it is clearly still possible (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34697"><span><span><span><strong><span…;). Thinner snowpacks at mid-elevations seem to be the prime suspects for these slides. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Today, wind loaded slopes have a CONSIDERABLE avalanche danger. All other slopes have a MODERATE danger.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The Big Sky area was the big winner in yesterday’s snowfall, with up to 8” of new snow. Fresh </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>will be up to a couple feet deep and easily triggered today. Keep your eyes out for signs of wind drifting and plan to avoid steep wind-drifted slopes. Pay careful attention to the texture of the snow beneath your feet or sled if you’re riding steep slopes that don’t seem wind affected. Cracks shooting out in front of you mean that the snow is in fact drifted and you need to get out of steep terrain ASAP.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is CONSIDERABLE on wind loaded slopes. Slopes sheltered from the wind have good stability and a LOW danger.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Less new snow fell in the mountains around Bozeman, so fresh </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> will be smaller and less widespread. Look for the same signs of wind drifting and be ready to back off steep slopes if you find unstable drifts. A skier caught and carried 100 ft on Wednesday in the Bridgers is a good reminder of the power of even a relatively small slide (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34703"><span><span><span><strong><span… and video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Slopes at higher elevations, beneath ridgelines and cornices are where you’re most likely to run into issues. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE on windloaded slopes and LOW on all other slopes.</span></span></span></span></span></span></p>
Skied a lap on Texas Meadow north of Bridger this afternoon. There were about 2" of new snow from today and 10-12" settled new snow that fell since last Friday. A few moderate gusts moved snow, but wind was not generally light. There was minimal fresh drifting, limited to ridgelines and openings in the trees.
A lot of ski tracks off the ridge north of the ski area. Only small loose snow slides were triggered from what I could tell, under mostly cloudy skies.
Snowpit at 7700', NE aspect showed a 6 foot deep, stable snowpack (profile attached). New snow creates the main avalanche concern, mainly where it is drifted into stiffer slabs. Dry Loose snow avalanches are a second concern for now.
All elevations in Island Park experienced heavy snowfall combined with high winds,this made for unstable wind slabs and cornices. Photo: K Allred
On this first day of spring, Ian and I toured up the northern ridge above Hebgen Lake today looking for weak snow near the base of the snowpack. Throughout the day, it snowed a little over an inch with bursts of sunshine in and out.
From the storm over the weekend, we noted about 1.5" of new and settled snow. We saw no cracking or collapsing or any other signs of instability.
We dug a snowpit at 8900' on a NE aspect (HS: 163), and while we found faceted snow at the bottom of the snowpit, beneath the dirt layer, we were only able to get propagation on this layer after extra hits. We got a few ECTN's (7, 17) higher up in the snowpack.
While we were encouraged by how few signs of instability we saw today, we are not ready to discount the possibility that avalanches could break on these weak layers, especially after seeing the persistent weak layer avalanche yesterday in the Taylor Fork. As always, if choosing to travel in steep terrain, use safe travel practices: one at a time on steep slopes, carry rescue gear, and regroup in safe zones.
All elevations in Island Park experienced heavy snowfall combined with high winds,this made for unstable wind slabs and cornices.
