Persistent Weak Layers and forecasting.

I have a good friend/IMGA guide/forecaster/rescue type person who been proposing that the forecasting community needs to change how they represent and convey PWL issues to the public for a few years now. His take is that a considerable rating due to a PWL is a lot different then considerable new snow issue. One is playing Russian roulette, the other could be possibly be navigated safely by a skilled party. (And several mags have brought this up recently) And the events of this season have show something is off.

Is it time to reevaluate the rating definitions and standards and make PWL issues it's own thing?
Like a 'no-go' color or PWL cross hatching for the rose? Something else?

I thought this was discussed online in like 2005/2006? If I remember correctly, part of the conversation was about having a new rating, “Moderate-X.” There was a healthy discussion about it on ttips, with many pros, including several from UAC, participating. What was the result of that discussion? Is it useful to move forward from that (and other) previous similar discussions?

I do not think a different way to convey the message about the type of hazard is a bad idea. I remember for a while the danger rose used to have “pockets” of higher hazard. Perhaps that style of addition information at the danger rose level can help convey the information and get readers to read the details of a forecast.

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Originally Posted by Redacted by user

It's a good idea and will likely help.

It's possible the Millcreek slide could have been mitigated if the backcountry skiing map had preferred skin routes as an overlay. The old man noted the skinner on that slope is supposed to go through the aspens to the right of the slide "based on prior lessons learned." The younger generations are eager to learn & I think would soak up that kind of knowledge if it were readily available.

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Oof. I kind of hate the idea of putting preferred skin tracks on a map. But maybe that's just a knee-jerk reaction on my part.

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I think it might be time to move away from consolidating the chance something will happen with the consequences of the outcome into one metric. This is already happening a bit with the advent of “spooky moderate & considerable”.

Ultimately I think we should use something similar to a JHA /HARC format (for BC skiing). That framework would likely help some skiers learn to conceptualize and internalize risk management.

I’m curious how other BC skier that have professional experience in fields with high safety standards and practices approach the risks of backcountry travel...so speak up or shoot me a pm

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Is it time to reevaluate the rating definitions and standards and make PWL issues it's own thing?

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Well, the current system has some holes that need a bit of work.

The issue is about route finding and safe travel, in other words, how to get around the mountains in winter.
Looking at the slide path in Wilson glade will reveal flagged trees all the way across the base with alleys from previous large slides cut out between the trees.
Haven't seen the monsters since early nineties? but avalanches run in 10-20-50-100 year cycles. Rather than focusing on danger ratings and filming video after video of digging snow pits for you tube, the focus should be on how in the hell you get around.
Don't need to spend half an hour digging when the hollow layer can be felt with a pole plant.
Terrain features can and do suggest safe paths on the up, which is where majority of the time is spent.

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Originally Posted by Bunion 2020

Well, the current system has some holes that need a bit of work.

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Agreed. How can we explain PWL in a visual manner that makes it easy for a casual BC user to understand how different it is than wet slides, wind slabs, or storm slabs? I know the simple answer here should be "education," but recent events with experienced users make me think we need to look deeper at a fundamental level.

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Originally Posted by snowaddict91

Agreed. How can we explain PWL in a visual manner that makes it easy for a casual BC user to understand how different it is than wet slides, wind slabs, or storm slabs? I know the simple answer here should be "education," but recent events with experienced users make me think we need to look deeper at a fundamental level.

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Not to be flip, but the audience for this information is the would be power users.

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Originally Posted by chickenNugget

Ultimately I think we should use something similar to a JHA /HARC format (for BC skiing). That framework would likely help some skiers learn to conceptualize and internalize risk management.

I’m curious how other BC skier that have professional experience in fields with high safety standards and practices approach the risks of backcountry travel...so speak up or shoot me a pm

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This is an interesting thought and one that’s crossed my mind on multiple occasions over the past couple weeks.

Also, there was an Avalanche Hour podcast with Chip Arenchild that mainly focused on risk management/mitigation in the workplace that I think would warrant a listen.

Have more to add to this later..

I think you start publishing risk matrices like shown in this google search as part of the avalanche forecast:

https://www.google.com/search?q=aval...-Cpx5hCjy2xTAM

None of it is new, but it's just not put in the actual forecast for everyone to see. Right now, it's left up to each individual user to even remember that type of risk-consequence matrix. Most probably don't visualize it. Of course, everything is left up to the individual, and the forecast center is not responsible for anyone's decisions.
From what's already out there, even an avalanche problem that falls on the very likely D3 size is still "moderate" or yellow hazard; for me, that's a total red zone.

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Originally Posted by wra

The issue is about route finding and safe travel, in other words, how to get around the mountains in winter.
Looking at the slide path in Wilson glade will reveal flagged trees all the way across the base with alleys from previous large slides cut out between the trees.
Haven't seen the monsters since early nineties? but avalanches run in 10-20-50-100 year cycles. Rather than focusing on danger ratings and filming video after video of digging snow pits for you tube, the focus should be on how in the hell you get around.
Don't need to spend half an hour digging when the hollow layer can be felt with a pole plant.
Terrain features can and do suggest safe paths on the up, which is where majority of the time is spent.

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This sounds like echos of the Jeremy Jones/ Krakauer session. So much good in that talk. I am going to watch it a second time. https://www.instagram.com/tv/CLDZsk9..._web_copy_link

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Originally Posted by snowaddict91

Agreed. How can we explain PWL in a visual manner that makes it easy for a casual BC user to understand how different it is than wet slides, wind slabs, or storm slabs? I know the simple answer here should be "education," but recent events with experienced users make me think we need to look deeper at a fundamental level.

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To explain it visually you have to show people video of it actually happening. This may sound funny but maybe one, of or some of the avalanche centers in conjunction with engineering colleges could have a contest similar to the south korean Skiing Robots Challenge. Have the robots simulate someone skinning and send them out under slopes in these circumstances. Not to mitigate but to educate. Everything could be recorded with sensors that detect surrounding slope angles, moment of collapse, depth of penetration at collapse, GPR or LIDAR, pretty much everything. Of course video too to show what happens to the human looking snobots in supposed safe zones.

It may sound funny (and the tuck is hilarious), but the technology is here. It was the first thing I thought of when I saw the video this morning.
https://www.youtube.com/watch?v=E-FAPKs1k-A

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Originally Posted by ryan14410

I think you start publishing risk matrices like shown in this google search as part of the avalanche forecast:

https://www.google.com/search?q=aval...-Cpx5hCjy2xTAM

None of it is new, but it's just not put in the actual forecast for everyone to see. Right now, it's left up to each individual user to even remember that type of risk-consequence matrix. Most probably don't visualize it. Of course, everything is left up to the individual, and the forecast center is not responsible for anyone's decisions.
From what's already out there, even an avalanche problem that falls on the very likely D3 size is still "moderate" or yellow hazard; for me, that's a total red zone.

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Where are you seeing an algorithm that results in a moderate danger rating for a very likely D3? If people really want to dig into how the danger ratings should be determined then you should search for and read the Conceptual Model of Avalanche Hazard.

Lots of good thoughts and ideas.

Now the curmudgeon in me comes out.

A large portion of the back country skiing population wants to be told if, "is it safe to go BC skiing today", never mind that the answer to that question will always be, "it depends".

They don't have the time or interest to deal with risk analysis or heuristics let alone reading the damned bulletins, just give them a danger rose and they have all the information they think they will need.

^Maybe don't make the danger rose/hazard rating accessible until you read the problems and previous (specified number of) days' obs.

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Originally Posted by powdork

^Maybe don't make the danger rose/hazard rating accessible until you read the problems and previous (specified number of) days' obs.

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My local forecasting center doesn't even publish a rose, narrative only. If you want to figure out the avalanche hazard you will need to spend more than 30 seconds looking at the report. This used to bug me, but after regularly checking UAC and CAIC and how buried the narrative is I think it's the right idea. Force people to read the narrative, not glance at a nifty graphic.

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Originally Posted by Bunion 2020

Lots of good thoughts and ideas.

Now the curmudgeon in me comes out.

A large portion of the back country skiing population wants to be told if, "is it safe to go BC skiing today", never mind that the answer to that question will always be, "it depends".

They don't have the time or interest to deal with risk analysis or heuristics let alone reading the damned bulletins, just give them a danger rose and they have all the information they think they will need.

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I'm pretty jaded at this point too, people are always finding new and exciting ways to screw up in the mountains. But that doesn't mean we shouldn't try.

I was reading about some of the successes and lessons learned about recent stop smoking campaigns.
An addictive habit that excites the brain but can kill you......and then there's smoking ;)

Criminalization and a "War" of some kind is clearly the answer here.

Whether there's a considerable or high danger doesn't equate to much difference in how to go about avoiding hazards. Instead of making the forecast more complicated, merging these two categories might convey a more straight forward, go/no go message. Then add the modifiers such as pwl, warming, terrain based manageability, etc.

This USAW presentation by Logan Cookler provides an example of how well a simplified system can work. They boil it all down to green vs. red runs for each days operations to avoid "runaways". Of course, they are bound to this as professionals, and there is continuity in knowledge of the terrain and avalanche history. All things in short supply these days amongst the growing mob of BC enthusiasts.

For dawn patrollers, the daily bulletins come too late in the day.

The Sierra avi center (Tahoe area) Instagram page includes the problem images in its IG posts. In that social media format, it takes one or two quick swipes for a user to see the images illustrating the types of problems, e.g., wind slab, storm slab, persistent slab.

An example of how Avalanche Canada presents PWLs (and other problems) in a separate tab. Recreationalists are taught to look at the ratings and the known avalanche problems as a minimum. Most years in the eastern Rockies PWLs exist as a listed avalanche problem for most of the season so it can lose a bit of meaning, but can be really useful for newer users as before you go out you're given the 1-3 avalanche problems to be on the lookout for. Then the chances and expected size gives you a quick understanding of the likelihood to consequence ratio.

Attachment 362257

I think adding skulls & crossbones to the rose might help in reaching people who can't be bothered to read the detailed forecast.

Seeing orange on there is obviously not a strong deterrent. A considerable likelihood of triggering a slide might not be seen as a big deal by some (I've expanded on this at length in another thread, considerable danger or wind slabs or new snow avalanches is something that can be seen as manageable under the right circumstances). Seing orange + skulls might remind people that the slides they can potentially get caught in are very high consequence ones that will most likely kill their asess.

Then again it would probably mean that people would treat orange without skulls as a greenlight...

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Originally Posted by powdork

To explain it visually you have to show people video of it actually happening. This may sound funny but maybe one, of or some of the avalanche centers in conjunction with engineering colleges could have a contest similar to the south korean Skiing Robots Challenge. Have the robots simulate someone skinning and send them out under slopes in these circumstances. Not to mitigate but to educate. Everything could be recorded with sensors that detect surrounding slope angles, moment of collapse, depth of penetration at collapse, GPR or LIDAR, pretty much everything. Of course video too to show what happens to the human looking snobots in supposed safe zones.

It may sound funny (and the tuck is hilarious), but the technology is here. It was the first thing I thought of when I saw the video this morning.

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Until you have them do it 10 times with no results, and then we've taught people it's not so bad?

I wasn't suggesting doing it live for people to watch. More of a slick M.A.D.D. type video. The triggering data i think would be interesting too.

But really I'm just trying to trick people into making a trail breaking bot.

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Originally Posted by Peyto

An example of how Avalanche Canada presents PWLs (and other problems) in a separate tab. Recreationalists are taught to look at the ratings and the known avalanche problems as a minimum. Most years in the eastern Rockies PWLs exist as a listed avalanche problem for most of the season so it can lose a bit of meaning, but can be really useful for newer users as before you go out you're given the 1-3 avalanche problems to be on the lookout for. Then the chances and expected size gives you a quick understanding of the likelihood to consequence ratio.

Attachment 362257

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"Most years in the eastern Rockies PWLs exist as a listed avalanche problem for most of the season so it can lose a bit of meaning"


I think this is a good point. When one issue shows up day in and day out at some point it will lose some impact for most users. I notice that UAC has been doing a good job of trying to write about the PWL differently day/week to day/week, and have started to even add zones on there that would be more likely to have this issue (i.e. zones with shallower packs). However, I do still think that when the exact same problem shows up on every report for 80 days straight people will start to minimize it (until an accident like wilson happens and it's the #1 focus now/again)