We got an ECTP18 result on a north aspect at 8600’ in the absarokas. It propagated on a small layer of facets 30cm down. Photo: C von Avis
Winds were ripping on the hike to Saddle Peak - almost knocking us over. If they had been just a few mph stronger, we would have been crawling. They were still finding snow to transport, and there were obvious plumes at discrete points along the ridge. Much of the snow was being blown to North Dakota while loading only in isolated places.
As soon as you got off the ridge, winds dropped to almost nothing, and we didn't find any wind slabs as we descended off the nose of Saddle into the North Central Gully. The skiing was excellent.
Further south, the bare rock area north of Bridger Peak had grown significantly as winds scoured a much larger area down to rock.
We rode up to the east Henderson Bench and back around to Scotch Bonnet and the Rasta Chutes. There was 5" of low-density new snow throughout the day and strong winds were actively drifting snow. Instability in the upper few inches was evident, with shooting cracks and small avalanches on steep drifts. In terrain unaffected by the wind, loose snow avalanches in the top few inches slid easily.
We dug on a northeast-facing slope ("Almost Died"), and two on southeast-facing slopes at two elevations in the Rasta Chutes. There was a recently buried weak layer 20-30 inches deep in all the pits that failed and propagated in two out of three--both the SE Rasta Pits (ECTP21 & ECTP25). I don't think we'll see a widespread avalanche cycle on this layer, but it is worth digging for and assessing before considering steep terrain. We saw Beau Fredlund at dinner and he came across an avalanche in Sheep Creek that broke 2-3 feet deep and 300 feet wide. I suspect it was this layer; however, the slope that avalanched was different in that it was a thin snowpack with some grass poking out. Our pits were 250-350cm DEEP!
The bottom line:
We got an ECTP18 result on a north aspect at 8600’ in the absarokas. It propagated on a small layer of facets 30cm down. We did not get any collapsing nor see signs of naturals or other activity on this layer, but we stuck to non-wind loaded slopes in the trees.
<p><span><span><span><span><span><span>The primary avalanche concern is </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> where yesterday’s strong wind drifted recent snow into slabs up to a couple feet thick. These slabs are possible for a person to trigger today. Avoid steep, recently wind-loaded terrain, typically found near ridgelines, identifiable by cornices above or a textured or rounded snow surface. For safer conditions seek out slopes sheltered from the wind, often found at middle and lower elevations where trees block the wind.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>There is a small chance for larger slabs to break 2-3 feet deep below last weekend’s snow. Yesterday near Cooke City skiers had a collapse and unstable test results on a weak layer below last weekend’s snow (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34725"><span><span><span><strong><span…;), and last weekend we saw similar layers near West Yellowstone and Island Park (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34631"><span><span><span><strong><span…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Near West Yellowstone, weak layers buried in late January continue to result in </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>up to 4 feet deep. Although these types of slides have been infrequent, avalanches were triggered on this layer yesterday and Wednesday (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34697"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>) in the Taylor Fork. These slides have not been huge, but large enough to be deadly, especially in much of the terrain where they have occurred, with trees or depressions at the bottom where snow can pile up deep. Select terrain with minimal terrain traps like trees, cliffs or gullies, carry avalanche rescue gear, and travel one at a time on steep slopes.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Human-triggered avalanches are possible and the avalanche danger is MODERATE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Near Bozeman and Big Sky </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 the primary avalanche concern. Yesterday, strong wind drifted recent snow into fresh slabs 6” to a couple feet thick. These slabs can avalanche under the weight of a person today. Below the recent snow we have not found concerning weak layers in the snowpack, and deeper avalanches are unlikely. Yesterday on Buck Ridge near Big Sky we dug four snowpits that did not show any potential instability below the recent snow, and we saw a couple small natural wind slab avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34724"><span><span><span><strong><span…, photo and video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). If you choose to travel on steep slopes, seek out slopes without recent wind-loading and dig down a couple feet to double check for potential weak layers or instability (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34715"><span><span><span><strong><span… and video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). The danger is MODERATE on wind-loaded slopes and LOW on all other slopes.</span></span></span></span></span></span></p>
We rode into all three Yellow Mule drainages and the head of Muddy Creek. It was snowing hard and wind was blowing strong this morning. In the afternoon, clouds lifted and snow let up. Skies remained mostly cloudy, but with high clouds there was decent visibility at the end of the day. There were 10-12" of new snow since last weekend, 2-4" low density fell this morning.
There was a small wind slab avalanche in McAtee (Photo) and a small wind slab in Beaver Creek.
On Mar 22 There was a small wind slab avalanche in McAtee (Photo) and a small wind slab in Beaver Creek. Photo: GNFAC
Skied south of Cooke today. Got an ECTP28 down 80cm on small facets above a MF crust that was buried on March 14. West aspect at 9500'. While filling in the snowpit I got a large collapse. This is the same layer we were getting ECTP results on earlier this week north of town.
We rode into all three Yellow Mule drainages and the head of Muddy Creek. It was snowing hard and wind was blowing strong this morning. In the afternoon, clouds lifted and snow let up. Skies remained mostly cloudy, but with high clouds there was decent visibility at the end of the day. There were 10-12" of new snow since last weekend, 2-4" low density fell this morning.
There was a small wind slab avalanche in McAtee (Photo) and a small wind slab in Beaver Creek.
We dug four snowpits, northerly aspects (one in each Yellow Mule), and one on a southeast aspect on the west side of the Second Yellow Mule. We did not find any unstable test scores or concerning layers. ECTNs within the new snow and ECTXs in some cases. In the southeast facing pit there was one .5" thick crust below this week's snow and a crust 2" thick below last weekend's snow (photo). Most pits had a dirt layer from last Sun/Mon strong-extreme winds, 10-12" deep. Total snow depth was 6-7 feet.
