MWAC article on "Moderate"

[neufox47]

MWAC wrote a good article about the Moderate avalanche rating and how people seem to think moderate means GO. The article was written partially in response to a large hard slab avy on Thursday 4/4/13 in an area that is typically considered "safer" terrain.

http://www.mountwashingtonavalanchec...spect-and-awe/

Here on the East Coast, we have an endemic problem of people ignoring current conditions and going because it's April and hey, last year the first weekend in April was great. If this avalanche had happened on Saturday, instead or Thursday, there probably would have been multiple people / groups entrained.

[icelanticskier]

the current rating system is kinda whack, imo. low and high is fine, but the moderate and considerable should be changed to "caution" and "extreme caution". or something else more effective/straightforward.

not skiing today rob?

rog

[Hacksaw]

http://www.mountwashingtonavalanchec...spect-and-awe/

That is an interesting article. I have not been a fan of the 5 level danger scale for years. But, as an avalanche professional I have to use it.... The avalanche community has been wrestling with the wordsmithing for years.

[goldenboy]

^ what would you prefer out of curiosity?

[Hacksaw]

Well, I'd rather see a four scale danger scale (Low, Moderate, High and Extreme) instead of the five scale that has Consideable in between Moderate and High.

Folks seem to get confused by Consideable. Under avalanche probability the book says "Consideable = Natural avalanches possible, human triggered slabs probable." While with Moderate it says, " Natural avalanches unlikely, human triggered slab releases possible." The differences between possible and probable confuse people. Especially, when they are out in the field and they see no natural avalanches (i.e., what is the avalanche danger if you see no natural avalanches?).

I personally like the snow stability rating system better (i.e., Very Good, Good, Fair, Poor and Very Poor) because it is based upon actual stability testing and described actual trigger loads (i.e., cornice falls, etc...).

But, I can't see the professional avalanche community going to a four level danger scale since that woud be going backwards.

In reality, there really is two levels of avalanche danger - its eaither going to avalanche or not avalanche. So, Low and Extreme are really not needed much. If its Extreme things are crashing down all over the place and you likely can't even get to the mountains.

Sorry, for such a fast short reply as I'm about to bolt out the door for a few days.

[icelanticskier]

In reality, there really is two levels of avalanche danger - its eaither going to avalanche or not avalanche.

this^^^^^^^^^^^^^^^^. end of story.

rog

[lynchdogger]

this^^^^^^^^^^^^^^^^. end of story.

rog

Wow! How profound. Snow science xtraordinaire!

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[Skihuckster]

I think it's all just info to keep in mind, but bottom line is that conditions are local and these days, anyone can get into the wrong place regardless of ratings. Recently remoted (from 100' away) a big slide that crowned more than 10' and ran on scree. Rating for that aspect/elevation was moderate. With that kind of reactivity I'd have called it high. Have also been out on high danger days and never felt safer.

Mother nature's a bitch. If you really want to be safe:
1. Read the report, decide to go or not
2. If you go, forget everything you read
3. Ski with people smarter, more mature, stronger, and with bigger shovels
4. Use your head, listen to your gut, always be smart about your route
5. Have fun and mind your slough

[neck beard]

I personally like the snow stability rating system better (i.e., Very Good, Good, Fair, Poor and Very Poor) because it is based upon actual stability testing and described actual trigger loads (i.e., cornice falls, etc...).

It describes stability (probability) well, but not size, consequence, spatial variability. I guess the difference between Stability and Risk/Hazard.

I know you know a lot more than me. Just thought I'd participate

[Hacksaw]

It describes stability (probability) well, but not size, consequence, spatial variability. I guess the difference between Stability and Risk/Hazard.

I really don't think that "avalanche size" matters. You can be killed as easy in a small avalanche (Snow Torents has lots of examples of this) as in a "big avalanche." Consequences, is more a matter of terrain. Spatial variability is a whole other matter, that the forecasters and researchers are all talking about.

[neufox47]

I really don't think that "avalanche size" matters. You can be killed as easy in a small avalanche (Snow Torents has lots of examples of this) as in a "big avalanche." Consequences, is more a matter of terrain. Spatial variability is a whole other matter, that the forecasters and researchers are all talking about.

Wouldn't potential avalanche size be better explained in the body of the report anyway?

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[neck beard]

I'd say nearly everything is better described within the body, particularly when the hazard is described in terms of Avalanche Problems, which is far more useful than a color or a number representing overall hazard.

As it stands in some forecasting circles, Avalanche Hazard eg, Considerable, is a function of: avalanche type, sensitivity to triggering, spatial distribution, destructive potential (size), and terrain character. Then overlay Human Factors and exposure. This makes good enough sense to me, but I really like hearing a wide range of opinions of others. I'm really only interested in leaning, not being right.

[old goat]

Unfortunately in France the written report is only available in French, although they at least give a diagram of risk by exposure and elevation. And the flags lump low and moderate together--yellow. With considerable and high together--checkered. Same in Italy I think.

[Hugh Conway]

Unfortunately in France the written report is only available in French, although they at least give a diagram of risk by exposure and elevation. And the flags lump low and moderate together--yellow. With considerable and high together--checkered. Same in Italy I think.

the flags are confusing (and I think I agree that having only 2 useful flags is silly - blacks bad) but it's not that bad

(from pistehors) increasing to 3 above 3000m, increasing to 4 below 3000m in Chamonix.

while 5 may not exist very often it's a useful everythings going wrong anchor end of the scale. given variability there's still plenty of ways to get caught on a 2 day.

[kootenayskier]

Reducing the full complexity within a mountain region to a single rating is the problem. I base my decisions on information (which can sometimes be found within public bulletins), not meaningless simplification.

[Hacksaw]

Reducing the full complexity within a mountain region to a single rating is the problem. I base my decisions on information (which can sometimes be found within public bulletins), not meaningless simplification.

I have to agree with you, for the most part. The avalanche centers try their best. But, the user's should realize that the bullitins are just the start of what is going on in the field. The users need to make their own observations and do their own stablity testing.

[FiveLarge]

Possible = less than 50% likelihood? Probable = more than 50% likelihood?
Basically possible means it could happen, but probably won't. Probable means it could happen, and likely will.

That's how I'd think of them, but not sure if that's correct.

Obviously, you can be out on a considerable day and not have it happen - there's a lot of room for "not happening" even at 51% likelihood.

[lynchdogger]

I have to agree with you, for the most part. The avalanche centers try their best. But, the user's should realize that the bullitins are just the start of what is going on in the field. The users need to make their own observations and do their own stablity testing.

Well said.

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[Vt-Freeheel]

MW Rangers appear to have been caught off guard by todays wet avi on a forcasted low day.

LINK

[icelanticskier]

MW Rangers appear to have been caught off guard by todays wet avi on a forcasted low day.

LINK

snow science isn't perfect, nor are humans no matter how edumacated they may be.

if jeff was able to predict that a particular block of ice would fall into a particular hole to create a sizeable wet slab avalanche after not a ton of rain, but lots of skier compaction over the previous days/weeks with some freeze/thaws thrown in for good measure, i'd surely be sending him a personal invite with limo pickup to the my next night of keno

rog

[johngfc]

Seems like a key issue is ambiguity, and this might be better addressed by a system with 3 or 4 levels like: low, caution, high, and extreme.

Low and extreme are obvious. Caution says maybe OK but dangerous in places due to local conditions, high is don't even think about dangerous lines. It's surely possible to forecast with greater resolution in some areas, but at least in CO conditions can vary dramatically depending on aspect, wind, etc and more levels seem more misleading than informative. This probably isn't an issue for experienced folks, but we're seeing a lot of backcountry use by people that put too much faith in forecasts and too little in on-site evaluation.