Trip Planning for Dillon Area

6700′     06-30 19:16
67℉
Wind3 mph
Gusts 9 mph
8945′     06/30 at 18:00
60℉
14″ Depth
7422′     06-30 19:16
68℉
Wind 3 mph
Gusts 8 mph
8,300′   06/30 at 18:00
58℉
0″ Depth

Snow Observations-Dillon Area

Dillon Area
Tobacco Root Mountains
Ramshorn - Tobacco Roots
Snow Obsdrvation includes images

Today we checked out the Ramshorn Peak basin in the Tobacco Roots. We skied a northeast aspect on the southern ridge of Ramshorn and found isolated pockets of wind loading, and an ECT revealed an ECTN 16 @ 20cm (HS 145cm). A couple of hand pits collected on this aspect suggest that this windslab has the potential to move (Q2 shears with easy to moderate difficulty) with new snow or sustained warmer temps. The warmer temps were noticeably effecting the snow at lower elevations and direct south aspects. We observed small pinwheels increase throughout the day on southern aspects, and noticed a large cornice failure on the southeast face of Ramshorn. We found a small and protected wind drift on a southern aspect and, with relative ease, kicked off the cornice (photo). 

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Dillon Area
Gravelly Range
Wolverine Basin
Snow Obsdrvation includes images

Snow was well below average for this time of year in the Gravelly Range. The snow pit was dug in Wolverine Basin near Standard Creek. A crust has formed on the very top of the snowpack which could be a layer of concerns during the next loading event. I did not have a crystal card on me but advanced faceting was occurring in the snowpack below 60 cm. There is a weak layer at 60cm that failed with the results as follows: CT 23 and ECTN 21.

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Dillon Area
East Pioneer Mountains
Rockslide

Rode sleds up trail and then skied to a high point of 9400ft. Generally supportable snowpack for skiing. Not as much for sledding. Lots of snow for this time of year. Good coverage. About 2 feet of new snow in past week (2 inches SWE). Dug to the ground at 9200ft northeast aspect. Height of snow 140 cm. Only real problem layer that was reactive in an extended column test was facets on the ground, their distribution was more spotty the higher we got in elevation, and the more deeply buried they are. No collapsing or cracking or other obvious signs of instability. But if someone were to trigger an avalanche on this layer of facets on the ground it would be catastrophic because it would release the entire winter's snowpack - about a 4 foot deep sslab

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Dillon Area
West Big Hole- Beaverhead Range
Rock Island
Snow Obsdrvation includes images

Naturally triggered Avalanche on North North East aspect. Heavy wind loading evident. The slide appeared to be recent, 24 to 48 hours old. 

 

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Dillon Area
West Pioneer Mountains
Shale Creek

Toured up to 8200 feet to North facing meadow that drops into Shale Creek. Lots of new downfall to navigate on the approach. Shallow snowpack. We dug a pit just below high point on a due North aaspect slope angle was 28 degrees. Height of snow was a paltry 50cm with a simple snow structure from surface to ground: 10cm Fist hard newish snow, 25cm 4finger soft sslab 10cm layer of Fist hard large grained faceted crystals (4mm), on top of a basal ice crust of 5cm on the ground. We performed an Extended Column Test and got ppropagationon the layer of facets on the crust at 12 lloadingsteps (ECTP 12). Cold temps have weakened the shallow snowpack which is noticeably less dense and supportable than it has been. 

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Dillon Area
East Pioneer Mountains
Comet Mountain - East Pioneers
Snow Obsdrvation includes images

Snowmobiled up to 9000ft, skinned up West face of Comet to 10K ft and skied low angle trees back to sled. Heavy windload with ccross loadingcommon on this slope. Dug a pit at 9200 ft, W aaspect 28 degree slope. Height of snow was 110 cm, about 3 and a half feet deep. Photo shows hand hardness profile in snowsnowpith faceted weak layers of concern in mid and lower snowpack. Extended column test had propagpropagation (ECTP 18) on large facets (see photo) around a crust about 40cm up from ground. No cracking or collapsing observed on tour. Good coverage for this time of year on this slope.

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Dillon Area
Maverick Mountain
Maverick Mountain - West Pioneers
Snow Obsdrvation includes images

Tour up Maverick Mountain before they open for the season to check how the snowpack is shaping up in the Pioneers; snowpack representative of backcountry. Got a Christmas eve gift when 6-8 inches of maverick 'white thunder' (+/- 5% density) fell overnight adding 30-50% to the total depth of snow. Dug quick pit on SE aspect 8100 feet and there is about 12-16 inches of low density snow with poles and skis going to ground. Dug a little higher on NE aspect 8200 feet where the snowpack is about twice as deep; about 2 feet plus and has a soft-ish slab in the mid-pack. We performed stability tests. ECTP12 10cm off ground. Softer slab on top of loose faceted snow on top of a hard crust made for propagation in the extended column test results. Surprisingly no collapsing and minimal, very localized cracking right around the skis. Ski quality greatly exceeded expectations!

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Relevant Photos

Displaying 1 - 3
  • Naturally triggered Avalanche on North North East aspect. Heavy wind loading evident. The slide appeared to be recent, 24 to 48 hours old. 

     

  • Snowmobiled up to 9000ft, skinned up West face of Comet to 10K ft and skied low angle trees back to sled. Heavy windload with cross loading common on this slope. Dug a pit at 9200 ft, W aspect, 28 degree slope. Height of snow was 110 cm, about 3 and a half feet deep. Photo shows hand hardness profile in snowpit with faceted weak layers of concern in mid and lower snowpack. Extended column test had propagation on 18 (ECTP 18) on large facets (see photo) around a crust about 40 cm up from ground. No cracking or collapsing observed on tour. Good coverage for this time of year on this slope.

  • Tour up Maverick Mountain before they open for the season to check how the snowpack is shaping up in the Pioneers; snowpack representative of backcountry. Got a Christmas eve gift when 6-8 inches of maverick 'white thunder' (+/- 5% density) fell overnight adding 30-50% to the total depth of snow. Dug quick pit on SE aspect 8100 feet and there is about 12-16 inches of low density snow with poles and skis going to ground. Dug a little higher on NE aspect 8200 feet where the snowpack is about twice as deep; about 2 feet plus and has a soft-ish slab in the mid-pack. We performed stability tests. ECTP12 10cm off ground. Softer slab on top of loose faceted snow on top of a hard crust made for propagation in the extended column test results. Surprisingly no collapsing and minimal, very localized cracking right around the skis. Ski quality greatly exceeded expectations!