Huge cycle in Montana; aka, I learned something from a Facebook comment :eek:

[powdork]

sorry for those of you not FB tolerant, but that's where the content is and I can't do anything about that, you can still see the pics and such here. But the fun and learning is in the comments for the opening pic on the Friends of the Flathead Avalanche Center's post on FB. One guy keeps insisting the forecasters are being unsafe, but then some kindness and knowledge is dropped on him
https://www.facebook.com/friendsoffl...type=3&theater

[srface_hoar]

Thanks for the link. A ton of good information on the Facebook site and some incredible pictures. Deep persistent weak layer and massive releases should put everyone on high alert, even in ski areas.

[t-the-east]

That picture is intense.

[LightRanger]

AvalancheGuys youtube channel has been super interesting lately too.
https://www.youtube.com/watch?v=MXPxJvSz-uk

[jamal]

one of the other pictures:

[Bunion 2020]

Meanwhile south of there.

[skiracer88_00]

That picture is intense.

I always wondered since these photos are common. Is it really safe to stand below the crown of something like that, knowing that same weak layer exists below the slab above the crown that didn't slide?

[toast2266]

I always wondered since these photos are common. Is it really safe to stand below the crown of something like that, knowing that same weak layer exists below the slab above the crown that didn't slide?

I take it you didn't read the link in OP's post.

[glademaster]

There's only one rule regarding Facefuck links: never, ever click a Facefuck link.

[powdork]

^Not true douchemaster. There's also the rule about never bumping a thread with a faceBook link.

[meter-man]

Worth quoting here for future reference:

Friends of the Flathead Avalanche Center Hi Chuck Savall and Steve Kuijt. Thanks for the comments. These are good points and we want to address them. We full-heartedly agree that experts and novices alike can all succumb to avalanche accidents. We aren't trying to model poor behavior so we want to explain our decision making and protocols for avalanche investigations, which is a part of our work as avalanche forecasters.

First, the objective of our visits to crowns is to document the snowpack structure and assess the timing, and thus weather parameters, that led to the avalanche release. Our center uses deep slab forecasting tools that rely on weak layer and structural characteristics. Our goal is to be able to accurately predict events like this, as we successfully did on Saturday, when we raised the danger to High and issued a Special Avalanche Bulletin for the Flathead Range.

Second, the mechanism for avalanche failure for a deep slab is the collapse of a weak layer. In this case, it is clear that the layer collapsed across the entire slope already, including the hangfire that didn't slide. I encourage you to read this paper, which describes how sintering of a weak layer after collapse causes a weak layer to strengthen about 15 times faster than a layer that hasn't collapsed. https://agupubs.onlinelibrary.wiley...../2005GL025104 It may seem counterintuitive, but after 12 hours or so, a slope that has already collapsed and avalanched is actually significantly stronger than a neighboring slope that hasn't collapsed:

Third, we are careful to wait for periods of improved stability and stable weather before conducting crown profiles like this, and we choose locations that aren't threatened by lingering concerns of cornice falls, sluffs, etc..

Lastly, we are careful not to travel on the hangfire itself, as a safety precaution. We acknowledge that there is a certain amount of risk that we accept in conducting daily fieldwork in avalanche country, just as there are other occupations in the public safety realm, such as firefighters, police officers, or search and rescue, that also accept risk with the ultimate goal of enhancing public safety. We attempt to minimize that risk at our forecast center through a series of peer-reviewed fieldwork plans, safety protocols and gear, and continued professional development and rescue training.

[t-the-east]

Well that escalated quickly