Data normalized for slope use

[neck beard]

Are there any recent data that separately shows frequency of skier/boarder accidental triggering by...

-slope angle

-slope aspect

...where that data has been normalized for slope use in each instance?

[CookieMonster]

Are there any recent data that separately shows frequency of skier/boarder accidental triggering by...

-slope angle

-slope aspect

...where that data has been normalized for slope use in each instance?

According to The Avalanche Handbook, citing work by McClung/Grimsdottir, aspect by itself is a poor predictor when slope use it taken into account. This isn't relevant to your question, but their data set and analysis may be relevant. You'll want to start here:

http://www.geog.ubc.ca/avalanche/pub...ing_NatHaz.pdf

[neck beard]

Thanks CookieMonster for the link. That looks like some reading.

At your prompt, looking now at my copy of The Avalanche Handbook, 3rd edition, page 224, figure 8.6. There is a chart that uses normalized data for likelihood of triggering by aspect, and references the paper you linked to. I think that is what I am after.

Regarding slope steepness and normalized data I found this at Wikipedia:

But when the incidence of human triggered avalanches are normalized by the rates of recreational use hazard increases uniformly with slope angle, and no significant difference in hazard for a given exposure direction can be found.

It gives the following source: Pascal Hageli, http://www.avisualanche.ca/publications.html

I am slowly scanning his papers for the relevant research.

[CookieMonster]

Happy to help! The link at avisualanche contains lots of good material, although I can't remember which of his work contains the info you need. Try his thesis?

Sent from my Paranoid Android using TGR forums.

[neck beard]

Thanks CookieMonster for the link. That looks like some reading.

Read it - interesting.

Lucky that CMH built that valuable database over the years. Unrealistic and hypothetical: it would be nice to investigate trigger probability by slope aspect where the only difference between aspects was solar radiation. No ski-quality slope-use bias, no wind loading bias etc. I don't know why I am thinking about this, just as a trivial summer hobby I guess - prompted possibly by recent exhortations that "the north sector is more dangerous because that is where most avalanches happen" during a rather casual presentation I saw on contemporary European reduction methods ["Munter (2003) recognises that the lack of usage data is a serious problem for his risk analysis" - I wish I had known that during the presentation!] I do not personally need the data to satisfy myself as my experience and intuition tells me the answer - and the answer changes with time-since-storm and time-of-day and time-of-season. I am glad that the CAC Slope Evaluation Card left slope aspect off the Terrain Character checklist.

Happy to help! The link at avisualanche contains lots of good material, although I can't remember which of his work contains the info you need. Try his thesis?

I kind of gave up. Few external links lead to actual papers, just the website of the journal that published them. Searching that website was fruitless.

[CookieMonster]

Read it - interesting.

Lucky that CMH built that valuable database over the years. Unrealistic and hypothetical: it would be nice to investigate trigger probability by slope aspect where the only difference between aspects was solar radiation. No ski-quality slope-use bias, no wind loading bias etc. I don't know why I am thinking about this, just as a trivial summer hobby I guess - prompted possibly by recent exhortations that "the north sector is more dangerous because that is where most avalanches happen" during a rather casual presentation I saw on contemporary European reduction methods ["Munter (2003) recognises that the lack of usage data is a serious problem for his risk analysis" - I wish I had known that during the presentation!] I do not personally need the data to satisfy myself as my experience and intuition tells me the answer - and the answer changes with time-since-storm and time-of-day and time-of-season. I am glad that the CAC Slope Evaluation Card left slope aspect off the Terrain Character checklist.

I kind of gave up. Few external links lead to actual papers, just the website of the journal that published them. Searching that website was fruitless.

You want his thesis: http://www.avisualanche.ca/downloads...EbookColor.pdf ( It's a big read, but worth it if you're feeling patient. )

Laura Adams' MSc thesis is astoundingly brilliant - if you haven't read it. I'd go as far as saying that -overall- it's the best thing I've ever read on the subject, and I learned a lot from the references too.

http://www.fsavalanche.com/NAC/techP...eses/adams.pdf