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  1. #51
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    Jan 2010
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    In the swamp
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    Quote Originally Posted by sandrock06 View Post
    Lesson learned, get one of these stickers for my ski poles.
    Attachment 265091
    Can one really eyeball the terrain with that graphic on a curved surface (pole)? Seems like a real inclinometer is better.

  2. #52
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    Dec 2006
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    Your Mom's House
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    Quote Originally Posted by The SnowShow View Post
    Can one really eyeball the terrain with that graphic on a curved surface (pole)? Seems like a real inclinometer is better.
    The poleclinometer is great for eyeballing. It's not as accurate as a real slopemeter. But it's good. Gets you within a couple degrees. And it's already in your hand.

  3. #53
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    Sep 2008
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    Not Brooklyn
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  4. #54
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    Oct 2008
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    off on yet another Tangent
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    Quote Originally Posted by I've seen black diamonds! View Post

    Or Theodolite:



    And for quick eyeballing (anything over 1/2 pole to one = increasing hazard potential):



    By matching the vertical lines to contours on 7.5' maps gets you the slope.
    Best regards, Terry
    (Direct Contact is best vs PMs)

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  5. #55
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    Sep 2009
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    heart in terrace, ass in cowtown
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    In reviewing the report I saw a snow profile done at the location. CT7 @ 35cms jumped out. I'm no avy pro and I do realize that pit data is only part of the equation but holy shit.

  6. #56
    Join Date
    May 2016
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    1,778
    Quote Originally Posted by Cravenmorhead View Post
    From the Report: There was an instructor in this group whose role was to teach the group how to understand, observe, and analyze the avalanche hazard and navigate through avalanche terrain. This accident is more complex than most because it involved a relatively large group of people, in a very structured environment, executing a detailed trip plan. In addition to the group’s plan, the instructor made a plan for the course based on his knowledge of the area and current conditions. This experience included multiple days in the field earlier that week, working in the area since mid-December, and work in the area each year for the last six. The instructor had additional local information at his disposal including information exchanges with other guides, avalanche safety operations, and recreationalists in the area.
    Thanks, I must have skipped over that when reading the report. So he was very familiar with the terrain. Seems like he would know all the areas that were potential avalanche zones there by heart, and there would be no need to interpret slopes from a map, or read an inclinometer, or whatever. He’d have to let his class go through that process, of course, but at some point if he saw they were flirting too close to a danger area, surely he would step in and steer a safer course. But he led the way.

    Perhaps he wasn’t anticipating that the group would sidestep so much to the right after he left them. Or maybe he really thought there was no danger. Ah, well, even experts make mistakes. I’m sure he feels awful.

  7. #57
    Join Date
    Feb 2012
    Location
    Truckee, CA
    Posts
    63
    CalTopo's first generation of slope angle shading was released in February 2012 - what feels like an unbelievably long 7 years ago. I think it's an incredibly useful tool for planning purposes, but the source data does have its limitations. I've always tried to present those limitations accurately and not over-sell the product, but figuring out how to best present data is a balancing act, particularly when there are other, non-winter uses for the slope angle shading layer. Coloring slopes 27 degrees and above, even though most people would use 30 as a "magic number", was specifically done to help provide a bit of error margin and compensate for the coarse resolution of the underlying DEM data.

    Complex terrain is almost always going to appear smoother on a map than it is in reality, which results in understating the slope angle of short rollovers. Even in a best-case scenario where CalTopo's slope layer were a verbatim match to reality, staying off (but not out from under, separate discussion) 30+ degree terrain would still have required hitting a 3-pixel wide, 70' gap between two 30+ degree colorations, which is a very small needle to thread. Of course reality is generally not going to match the map with anything close to that level of precision.

    It's a sad event that we only have secondhand info on and I'm not looking to criticize those involved, but I'm also struggling to wrap my head around exactly what happened and what their thought process was - I can't get the "should I be changing something with the slope angle shading layer" thought out of my head. While the CAIC report hones in on slope angle shading, I can't tell if the students simply used it to pre-plan a route, if they were actively using it for micro-navigation on a phone, or if the guide was reliant on it as well. It does make me wonder how commonly the layer is mis-used for micro-routefinding, and whether there are changes that would help address the issue.

  8. #58
    Join Date
    Dec 2008
    Posts
    499
    Quote Originally Posted by mattyj View Post
    CalTopo's first generation of slope angle shading was released in February 2012 - what feels like an unbelievably long 7 years ago. I think it's an incredibly useful tool for planning purposes, but the source data does have its limitations. I've always tried to present those limitations accurately and not over-sell the product, but figuring out how to best present data is a balancing act, particularly when there are other, non-winter uses for the slope angle shading layer. Coloring slopes 27 degrees and above, even though most people would use 30 as a "magic number", was specifically done to help provide a bit of error margin and compensate for the coarse resolution of the underlying DEM data.

    Complex terrain is almost always going to appear smoother on a map than it is in reality, which results in understating the slope angle of short rollovers. Even in a best-case scenario where CalTopo's slope layer were a verbatim match to reality, staying off (but not out from under, separate discussion) 30+ degree terrain would still have required hitting a 3-pixel wide, 70' gap between two 30+ degree colorations, which is a very small needle to thread. Of course reality is generally not going to match the map with anything close to that level of precision.

    It's a sad event that we only have secondhand info on and I'm not looking to criticize those involved, but I'm also struggling to wrap my head around exactly what happened and what their thought process was - I can't get the "should I be changing something with the slope angle shading layer" thought out of my head. While the CAIC report hones in on slope angle shading, I can't tell if the students simply used it to pre-plan a route, if they were actively using it for micro-navigation on a phone, or if the guide was reliant on it as well. It does make me wonder how commonly the layer is mis-used for micro-routefinding, and whether there are changes that would help address the issue.
    Disclaimer: have not read the report in detail, and being Norwegian I have no knowledge of the maps/GPS etc being used here.


    However, in my experience there is three things to remember when using GIS in route planning.

    1) As stated several times already, microterrain will disapear between contours.

    2) Wind transport will affect the visual impression. Steep terrain may be hidden by a even surface, or gentle terrain may still hold snow bulges or cornices.

    3) One of the bigger problems when using the NGIs avalanche maps in Norway, by default they will only show starting zones, not runouts.
    Google ngi+skredkart

    This is especially important at danger 3 or above and/or whenever the forecast warns about the possibilty to trigger avalanches at a distance.

    To mitigate 3) the Norwegian army uses maps that differ between terrain that holds potential starting zones, and they terrain that might be affected by the avalanche.

    You can construct these yourself, or you can use the 3:1 rule. Your horizontal stand-off should be three times the vertical drop of the potential starting zone. The 3:1 is extremely conservative, ment to handle any and all avalanche conditions.

    Google norwegian+army+avalanche+maps, for several papers and the Norwegian army safe travel / avalanche literature.
    Also a good read regarding winter navigation, crossing ice etc.

    There is a english version

  9. #59
    Join Date
    Apr 2004
    Location
    Holy Mt.
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    515
    Oh my god, but people love to make everything so complicated. Skiing has gotten gay, thanks iamgay.

  10. #60
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    Sep 2005
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    PRB
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    21,079
    wtf? this is your 1st post in months, in the Slide Zone on a thread about an incident where someone died?
    Last edited by Danno; 01-18-2019 at 09:46 AM.
    "fuck off you asshat gaper shit for brains fucktard wanker." - Jesus Christ
    "She was tossing her bean salad with the vigor of a Drunken Pop princess so I walked out of the corner and said.... "need a hand?"" - Odin

  11. #61
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    Quote Originally Posted by kailas View Post
    Oh my god, but people love to make everything so complicated. Skiing has gotten gay, thanks iamgay.
    What Danno said. What in the fuck are you trying to say anyway?

  12. #62
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    Aug 2008
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    Denver, CO
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    1,744
    Quote Originally Posted by mattyj View Post
    CalTopo's first generation of slope angle shading was released in February 2012 - what feels like an unbelievably long 7 years ago. I think it's an incredibly useful tool for planning purposes, but the source data does have its limitations. I've always tried to present those limitations accurately and not over-sell the product, but figuring out how to best present data is a balancing act, particularly when there are other, non-winter uses for the slope angle shading layer. Coloring slopes 27 degrees and above, even though most people would use 30 as a "magic number", was specifically done to help provide a bit of error margin and compensate for the coarse resolution of the underlying DEM data.

    Complex terrain is almost always going to appear smoother on a map than it is in reality, which results in understating the slope angle of short rollovers. Even in a best-case scenario where CalTopo's slope layer were a verbatim match to reality, staying off (but not out from under, separate discussion) 30+ degree terrain would still have required hitting a 3-pixel wide, 70' gap between two 30+ degree colorations, which is a very small needle to thread. Of course reality is generally not going to match the map with anything close to that level of precision.

    It's a sad event that we only have secondhand info on and I'm not looking to criticize those involved, but I'm also struggling to wrap my head around exactly what happened and what their thought process was - I can't get the "should I be changing something with the slope angle shading layer" thought out of my head. While the CAIC report hones in on slope angle shading, I can't tell if the students simply used it to pre-plan a route, if they were actively using it for micro-navigation on a phone, or if the guide was reliant on it as well. It does make me wonder how commonly the layer is mis-used for micro-routefinding, and whether there are changes that would help address the issue.
    First off, thanks for CalTopo. It has been an indispensable tool in my tour planning for the past few years. That being said, I learned a lot from this report and many of the things discussed are things I am guilty of. I have spent a lot of time scouring maps looking for high alpine lines in Colorado that are gray or have small amounts of yellow/orange on CalTopo. I have definitely gotten into the field on lines I discovered in this manner and felt like I may be flirting with some danger and that some of these lines have steeper sections than what I thought I would find. I realized while reading this report that perhaps I myself was putting too much reliance on the slope shading feature and that while I could still use it to plan routes, I needed to do a better job of evaluating slope angle in the field. As for changes to CalTopo? I can't think of any. I think it was one of the small mistakes this group made in a collection of mistakes. I'm just glad to have the extremely well written report from CAIC to learn from.
    ((. The joy I get from skiing...
    .))
    ((. That's worth living for.
    .))

  13. #63
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    Dec 2009
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    Paradise
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  14. #64
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    Aug 2007
    Posts
    5,373
    Taking a class to stay alive in the backcountry and then dying while taking a class in the backcountry. Tragic irony, RIP.

    He had two daughters like me. I can guess he was trying to be a responsible father by learning as much as he could so he could always be there for them.

  15. #65
    Join Date
    Jan 2009
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    Boulder/Tetons
    Posts
    455
    The Ashcroft avy report is out... some similar sadness in terms of the fathers involved and the circumstances of that fatality.

  16. #66
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    Mar 2014
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    It's Full of Stars....
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    SAS just linked this on their FB page.....

    https://www.powder.com/stories/your-...6cX7ILkOusM.01

  17. #67
    Join Date
    May 2011
    Location
    Sonoma & Truckee
    Posts
    11,050
    Quote Originally Posted by mattyj View Post
    CalTopo's first generation of slope angle shading was released in February 2012 - what feels like an unbelievably long 7 years ago. I think it's an incredibly useful tool for planning purposes, but the source data does have its limitations. I've always tried to present those limitations accurately and not over-sell the product, but figuring out how to best present data is a balancing act, particularly when there are other, non-winter uses for the slope angle shading layer. Coloring slopes 27 degrees and above, even though most people would use 30 as a "magic number", was specifically done to help provide a bit of error margin and compensate for the coarse resolution of the underlying DEM data.

    Complex terrain is almost always going to appear smoother on a map than it is in reality, which results in understating the slope angle of short rollovers. Even in a best-case scenario where CalTopo's slope layer were a verbatim match to reality, staying off (but not out from under, separate discussion) 30+ degree terrain would still have required hitting a 3-pixel wide, 70' gap between two 30+ degree colorations, which is a very small needle to thread. Of course reality is generally not going to match the map with anything close to that level of precision.

    It's a sad event that we only have secondhand info on and I'm not looking to criticize those involved, but I'm also struggling to wrap my head around exactly what happened and what their thought process was - I can't get the "should I be changing something with the slope angle shading layer" thought out of my head. While the CAIC report hones in on slope angle shading, I can't tell if the students simply used it to pre-plan a route, if they were actively using it for micro-navigation on a phone, or if the guide was reliant on it as well. It does make me wonder how commonly the layer is mis-used for micro-routefinding, and whether there are changes that would help address the issue.
    I didn't realize CalTopo was your site! Awesome - I'm a big fan. I may have been the one responsible for (inadvertently) blowing up your servers during the Sonoma County fires.

  18. #68
    Join Date
    Apr 2004
    Location
    Holy Mt.
    Posts
    515
    The guide that led them to that terrain was supposedly an 'avi pro.' The fact is conditions above tree line were suspect, so go below tree line.

  19. #69
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    Apr 2004
    Location
    Holy Mt.
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    515
    Quote Originally Posted by billyk View Post
    Thanks, I must have skipped over that when reading the report. So he was very familiar with the terrain. Seems like he would know all the areas that were potential avalanche zones there by heart, and there would be no need to interpret slopes from a map, or read an inclinometer, or whatever. He’d have to let his class go through that process, of course, but at some point if he saw they were flirting too close to a danger area, surely he would step in and steer a safer course. But he led the way.

    Perhaps he wasn’t anticipating that the group would sidestep so much to the right after he left them. Or maybe he really thought there was no danger. Ah, well, even experts make mistakes. I’m sure he feels awful.
    The guide was incompetent, that much is obvious.

  20. #70
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    Quote Originally Posted by kailas View Post
    The guide was incompetent, that much is obvious.
    There’s been a lot of recent discussion in this sub forum about why you might want not to be a judgemental, finger-pointing douche. Consider checking out some of the other threads, like this:
    https://www.tetongravity.com/forums/...15#post5595415

    And read the quote from Bruce Tremper in this post:
    https://www.tetongravity.com/forums/...99#post5602299
    Don’t give up until.

  21. #71
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    Oct 2003
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    OOTAH
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    2,446
    Quote Originally Posted by Meadow Skipper View Post
    There’s been a lot of recent discussion in this sub forum about why you might want not to be a judgemental, finger-pointing douche. Consider checking out some of the other threads, like this:
    https://www.tetongravity.com/forums/...15#post5595415

    And read the quote from Bruce Tremper in this post:
    https://www.tetongravity.com/forums/...99#post5602299
    I honestly dont understand the need for people o come here and be smug and self righteous, I dont know why but it bugs the shit out of me. I suppose since in my 28 years of touring, i have made pretty much every mistake that has been made in this sub forum. I have also learned a ton by hearing and reading about other peoples accidents and near accidents. I still pick up stuff by listening.
    I appreciated in here where someone said they always designate one person to be the naysayer on the tour, I really like that and we have incorporated into the standard protocol. Something I would have never learned if people didn't just come here to proclaim how much smarter they are and how dumb other people are. We all know a mistake was made, so why come to just state the obvious?
    Samuel L. Jackson as Jules Winnfield: Oh, I'm sorry. Did I break your concentration?

  22. #72
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    Aug 2006
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    4,231
    Instructor that day, not a guide.

  23. #73
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    PRB
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    Quote Originally Posted by kailas View Post
    The guide that led them to that terrain was supposedly an 'avi pro.' The fact is conditions above tree line were suspect, so go below tree line.
    It was an avy 2 class, and he was an instructor not a guide. And as an avy 2 class, they're not supposed to just avoid suspect terrain and ski below treeline. They wouldn't learn a damn thing doing that.
    "fuck off you asshat gaper shit for brains fucktard wanker." - Jesus Christ
    "She was tossing her bean salad with the vigor of a Drunken Pop princess so I walked out of the corner and said.... "need a hand?"" - Odin

  24. #74
    Join Date
    Feb 2005
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    North Vancouver/Whistler
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    11,294
    Be aware that kailas is a known waste of space. If he died in a treewell. Slowly. Nobody should shed a tear

  25. #75
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    Quote Originally Posted by LeeLau View Post
    Be aware that kailas is a known waste of space. If he died in a treewell. Slowly. Nobody should shed a tear
    Noted.
    Don’t give up until.

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