Photo of a recent natural avalanche north of Cooke City, observed today. A S, SE aspect in Sheep Creek at about 9000'. Seems like it likely occurred yesterday.
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:
Significant amounts of recent snow and strong wind this afternoon, and more snow forecast for tonight. Avalanches on wind-loaded slopes are likely to very likely. Currently, I would avoid all the big, heavily wind-loaded terrain in Cooke City. This is were you'll trigger a slide and it has the potential to break a few feet deep.
Dig down three feet to test for instability before skiing or riding steeper non-wind-loaded terrain.
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.
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 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').
Today we saw a D2 slab avalanche at Goose Lake, E facing, 10800 ft. We estimate this avalanche to have ran in the early hours of 3/17. This was the only avalanche we observed in the past 4 days.
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.