From e-mail: "...a photo of what appeared to be a natural D2 underneath the Maid today [2/19/21]." Photo: H. Coppolillo
I toured into Blackmore with a client this morning and observed an old snow avalanche at 9600' on the east face of Mt Blackmore. I was there the day before and didn't see any evidence of avalanche activity; strong overnight winds with ample snow available for transport appeared to be enough to tip the scales.
You guys probably already know about this one, but if not then here’s a photo of what appeared to be a natural D2 underneath the Maid today.
From email: "While on tour today above the canyon, we observed various snow surfaces. We found heavily windloaded slopes on E/NE aspects. Solar aspects began to develop rollers as rocks began to heat up around noon. We observed a small avalanche on E slope a drainage away, roughly 20 feet wide. While ascending a ridgeline at 7500 elevation, we had a massive woomph and crack that spread 100 feet from the ridge to a roller in the fall line." Photo: Tommy S.
At 6450 feet on a north facing aspect on Little Mt. Ellis I found a snow depth of 75 cm. I dug a pit and got a Ct -7. Ect - 18, both failing on ground facets at 15-20 cm depth. I didn’t see any slides, but I did feel and hear one whumpf on the way up. Needless to say, I kept it low angle on the way down. Hope you can use this data. Thanks for all the great work you do!
While on tour today above the canyon, we observed various snow surfaces. We found heavily windloaded slopes on E/NE aspects. Solar aspects began to develop rollers as rocks began to heat up around noon. We observed a small avalanche on E slope a drainage away, roughly 20 feet wide. While ascending a ridgeline at 7500 elevation, we had a massive woomph and crack that spread 100 feet from the ridge to a roller in the fall line. We decided to ski our skin track back down to the car.
<p>Strong winds yesterday drifted the abundant fresh snow and continued to load many slopes. Around noon yesterday, an avalanche broke naturally, several feet deep, on a heavily wind-loaded slope in the Bridger Range, south of Saddle Peak (<a href="https://www.mtavalanche.com/images/21/natural-avalanche-south-saddle-pe…;). With a bit more new snow and continued winds, similar slides will be easily triggered today, especially on wind-loaded slopes. Avalanches that initially break beneath the new and wind-drifted snow will likely step down to the lower weak layers, mid-pack or near the ground. </p>
<p>Continued snowfall may obscure subtler signs of wind-loading, but be especially skeptical of slopes beneath cornices and those with large drifted pillows directly below ridgelines. Avoid travelling on, or beneath, slopes steeper than 30 degrees. Conservative decision making is essential today. With natural avalanches possible and human triggered slides likely, the avalanche danger is rated CONSIDERABLE.</p>
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<p>With a similar weak snowpack structure in the southern ranges, the consequences of triggering a slide are the same as up north, but without as much new snow the likelihood is a bit less. A large snowmobile triggered slide in Cabin Creek is a good reminder of the sort of slide we’re worried about (<a href="https://www.mtavalanche.com/node/24253"><u>details</u></a>). With large, deadly avalanches a real possibility, avoiding all avalanche terrain is a very reasonable strategy. If you are going to poke on to steeper slopes, dig a snowpit and do some snowpack tests before committing and then only expose one person at a time. The avalanche danger is MODERATE today.</p>
<p>Around Cooke City, the primary concern is avalanches breaking on wind-loaded slopes. A snowmobile triggered slide yesterday on Crown Butte highlights this concern (<a href="https://www.mtavalanche.com/images/21/snowmobile-triggered-slide-crown-…;, <a href="https://www.mtavalanche.com/images/21/snowmobile-triggered-slide-crown-…;). More snowfall and wind today will create fresh drifts on top of the older drifts and you could trigger either. Dave was in Cooke City the last few days and is cautiously optimistic about the strength of the lower snowpack, but didn’t rule out the possibility of triggering a deeper slide if you hit an atypically thin spot (<a href="https://www.youtube.com/watch?v=tzo-kbMbDUc"><strong><u>Wednesday video</u></strong></a>, <a href="https://www.youtube.com/watch?v=w4BEGFLhQWY"><strong><u>Thursday video</u></strong></a>). For today the avalanche danger is rated MODERATE.</p>
<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Snowmobile triggered slide on Crown Butte, 2/18/2021.
