22-23

Mt Ellis Sat Dec 17th

Date
Activity
Skiing

Skied a few laps on Ellis today, E through NE aspects

No slab avalanche activity was observed (minor sluffing on steep, cold slopes)

Got off the skin track in a few places and no whumphing or cracking

Light to moderate ridgetop winds from W and SW

Trees holding snow; no drifting/ blowing snow on Ellis 

Saw A LOT of blowing/ drifting snow toward Hyalite and the Spanish Peaks at elevations above 8000'

Average HS on Ellis summit ridge 100 cm; average ski penetration 35 cm

Dug a quick test pit on a NE aspect at ~7800' (30 deg slope)

Pit results: HS 130 cm; CT 21 BRK at 85 cm; ECTX

No signs of instability; great skiing. Yay!

 

 

 

Region
Northern Gallatin
Location (from list)
Mt Ellis
Observer Name
Alexis Alloway

GNFAC Avalanche Forecast for Sat Dec 17, 2022

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Newly formed and thickening wind drifts will easily avalanche today under the weight of a skier or rider. Yesterday, a skier triggered an avalanche that broke 2-4 ft deep and 150 ft wide in wind drifted snow on Saddle Peak (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27226"><span><span><span><strong><span… and photo</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Thankfully, while he was caught and carried 500 vertical ft he wasn’t buried or otherwise injured. Today is the sort of day that catches people off guard - there isn’t any new snow, but increasing winds are drifting the plentiful soft snow at the surface into fresh drifts. Wind drifts </span></span></span></span></span></span><span><span><span><strong><em><span>will</span></em></strong></span></span></span><span><span><span><span><span><span> avalanche today on steep slopes. Avoid these steep, wind drifted slopes.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Avalanches can also break on weak layers deeper in the snowpack (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=En1DxtBkHt0"><span><span><span><strong>… Ridge video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://youtu.be/TkUux4F7dV8"><span><span><span><strong><span><u><span>… Ellis video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Imagine if that avalanche on Saddle Peak had broken down into the weak layers that we know are there because Alex found them last weekend on the Football Field (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=XrYqTxRt4go"><span><span><span><strong>…;). It would have been several feet deeper and likely much wider and even more powerful. Dig to look for these layers before getting on any steep slope.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>With increasing wind drifting today, human triggered avalanches are likely on wind-loaded slopes and the avalanche danger is CONSIDERABLE. The danger is MODERATE on all other slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Avalanches breaking on the widespread weak layers buried 2-4 ft deep are our primary concern today. Without loading, these slides are slowly becoming less likely, but if they break, they’ll be large and powerful. Natural avalanches earlier this week near Cooke City show that these weak layers can’t yet be discounted (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27218"><span><span><span><strong><span…;). Terrain selection remains the best way to minimize your chance of triggering a large avalanche - by staying off of and out from under slopes steeper than 30 degrees (</span></span></span></span></span></span><a href="http://www.mtavalanche.com/index.php/node/27148"><span><span><span><str…; from an avalanche triggered from below last week). If you are going to ride steep slopes, dig to assess the weak layers first. Avalanches remain possible and the danger is rated MODERATE.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>If you get out, please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).&nbsp;</span></span></span></span></span></span></p>

<p>&nbsp;</p>

<p>Avalanches breaking on the weak layers buried 2-4 ft deep are our primary concern today. Without loading, these slides are slowly becoming less likely, but if they break, they’ll be large and powerful. Terrain selection remains the best way to minimize your chance of triggering a large avalanche - by staying off of and out from under slopes steeper than 30 degrees. If you are going to ride steep slopes, dig to assess the weak layers first.</p>

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Skier caught and carried on Saddle Peak

Saddle Peak
Bridger Range
Code
SS-ASu-R2-D2.5-I
Elevation
9000
Aspect
SE
Latitude
45.79430
Longitude
-110.93600
Notes

Skier triggered avalanche on Saddle Peak. 12/16/22.

From obs: "I got to the top of the south summit around 11am with lots of active wind loading. I traversed the ridge line for a couple hundred feet, kicking away at small cornices to see if I could trigger anything. Got two small 6-8” deep soft slabs to propagate 10’ wide and a couple hundred vertical but nothing major. The ridge line is too rocky to traverse right now so I dropped onto the face, still staying near the ridge line. A hundred feet or so further across my traverse, it got deep. Cross loading from the north grew a drift that was thigh deep at least. Very cautiously I tried to regain some elevation to get above anything that might pop off. A few steps up the drift, I heard a whumph and it started to slide. I would estimate 2-4’ deep, 150’ wide. It immediately caught my skis and started taking me down. I pointed them down hill and started to pick up speed hoping I could cut out of it. It started getting very deep and turbulent so after 200-300’ I pulled my airbag, while still trying to stay on my feet. Thankfully, I was able to stay up and cut out of the slide roughly 500’ below the summit. It ran full length into the bottom of Argentina bowl and south gut with a massive powder cloud. Way too close of a call. I skied down the avalanche path then back to the resort with my airbag deployed in case of any other slides coming down. Made it back to the resort touched base with ski patrol to alert them of the slide, give them information on my condition and the possibility of other skiers out there (no possibility, I was first person up and didn’t see anyone ascending from the gate when I crossed to south summit) and headed home."

Number of slides
1
Number caught
1
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
2
D size
2.5
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
36.0 inches
Vertical Fall
1000ft
Slab Width
150.00ft
Images
Saddle avalanche with crown and toe marked
Snow Observation Source
Skier caught in avalanche on Saddle Peak
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
22-23

Skier triggered avalanche on Saddle Peak. 12/16/22.

From obs: "I would estimate 2-4’ deep, 150’ wide. ... It ran full length into the bottom of Argentina bowl and south gut with a massive powder cloud. "
 

Avalanche Details: Skier caught and carried on Saddle Peak
Forecast link: GNFAC Avalanche Forecast for Sat Dec 17, 2022GNFAC Avalanche Forecast for Sun Dec 18, 2022
Bridger Range, 2022-12-17
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    • Skier caught in avalanche on Saddle Peak

    Date
    Activity
    Skiing

    I got to the top of the south summit around 11am with lots of active wind loading. I traversed the ridge line for a couple hundred feet, kicking away at small cornices to see if I could trigger anything. Got two small 6-8” deep soft slabs to propagate 10’ wide and a couple hundred vertical but nothing major. The ridge line is too rocky to traverse right now so I dropped onto the face, still staying near the ridge line. A hundred feet or so further across my traverse, it got deep. Cross loading from the north grew a drift that was thigh deep at least. Very cautiously I tried to regain some elevation to get above anything that might pop off. A few steps up the drift, I heard a whumph and it started to slide. I would estimate 2-4’ deep, 150’ wide. It immediately caught my skis and started taking me down. I pointed them down hill and started to pick up speed hoping I could cut out of it. It started getting very deep and turbulent so after 200-300’ I pulled my airbag, while still trying to stay on my feet. Thankfully, I was able to stay up and cut out of the slide roughly 500’ below the summit. It ran full length into the bottom of Argentina bowl and south gut with a massive powder cloud. Way too close of a call. I skied down the avalanche path then back to the resort with my airbag deployed in case of any other slides coming down. Made it back to the resort touched base with ski patrol to alert them of the slide, give them information on my condition and the possibility of other skiers out there (no possibility, I was first person up and didn’t see anyone ascending from the gate when I crossed to south summit) and headed home.
     

    Region
    Bridger Range
    Location (from list)
    Saddle Peak

    Mt. Ellis

    Date
    Activity
    Skiing

    Didn't see any windslabs yet on NE facing burn scar. Just like ~2ft of loose fluffy snow. Trees still have snow on them, so wind probably hasn't been that bad.

    Region
    Northern Gallatin
    Location (from list)
    Mt Ellis
    Observer Name
    Daniel

    Little Ellis observations

    Date
    Activity
    Skiing

    I got out for a low-angle morning lap with some good folks this morning on Little Ellis and thought I'd send along a couple quick take homes:

    1. We found 6 ~ 12" of new snow on our way up (and it skied excellently)

    2. We saw no obvious signs of instability (cracking, collapsing, or recent avalanches)

    3. We observed no wind during our outing (630 - 830am) and found no wind affected snow

    4. Temperatures seemed inverted with slightly warmer temps at ridgetop vs. cool air pooled at the trailhead

    5. Dug a quick handpit at the top transition and found a supportable pencil hard crust underneath the new fallen snow with well-developed large-grained facets below that... but the quick hole was in the upper scree/rock garden... so I'd expect it to harbor more basal faceted snow.

    Region
    Northern Gallatin
    Location (from list)
    Mt Ellis
    Observer Name
    Zach Miller
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