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Detection of hidden crevasses

  1. Feb 19, 2016 #1
    Hello there,

    I want to do a alpine solo tour at the beginning of april.
    Crevasses, which are covert by snow are very insidious. This is why solo tours are more of a gambling game.
    The basic idea is: Using a detector which can make a differentiation between a solid subsoil of ice, and a crevasse.

    For example Satellites use radar signals, to measure the thickness of ice plateaus by use of reflection at material boundaries. In my case, I only want a binary information: Can I take a step or not?

    Do you have an idea how that differentiation can be accomplished?
    I mean there should always be some difference between the scan of a solid subsoil and of a hollow underground. The question is, how to make that difference maximally distinctive.


    Which kind of signal is most appropriate for that? Also radars?
     
    Last edited: Feb 19, 2016
  2. jcsd
  3. Feb 19, 2016 #2

    Nidum

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  4. Feb 28, 2016 #3
    You are exactly right that crevasses can be rather insidious. They are not really that difficult to identify or predict. Being well acquainted with snow and the formation of crevasses is also very helpful. If you have access to a typicall mountaineering group such as the Mountaineers or Mazamas they they would be more than to lead some trips for education. Alternatively one could study a book like "Freedom of the Hills."

    What sort of trip are you planning? Radio and Radar type detection devices are much heavier than I would want to carry very far in the snow.
     
  5. Feb 29, 2016 #4
    Yes, that imagination was rather utopic. I planned a trip to Switzerland, Berner Oberland (the Eiger is also in that region).
    For me as a student such a guided tour is not affordable. But I found another mountain (in that same region) which has a smaller (due to global warming), bypassable glacier. Still dangerous...
    Nevertheless, its an interesting topic, and I will come back to that after the exams.
    With Portable masers (lasers at 500MHz) that would be a cakewalk, if they existed.
    But I spoke to one of the persons, who wrote the paper, that @Nidum has posted, and he told me, that actually the detection is very unreliable, because the signal energy is so badly attenuated, and there are a lot of disturbing factors. What this research group has achieved, is to detect some crevasses, after passing them completely with the antennas. They show up in the radiogram as hyperbolas. Then this hyperbola has to be identified via image processing.

    Predicting them by eye is sometimes impossible:



    But if someone has a feeling for it, one certainly can predict the route of it with regard to the topology. For example, it is better to rest in a trough, than at a zenith, like the guy in the video did.
     
  6. Feb 29, 2016 #5
    Anton, it is great to hear that a considered mind is prevailing. There is a possibly a few misunderstanding from my short post. The groups that I referred to are very low cost clubs. Also many schools have outdoor activity clubs that are part of the student union. It should not be very hard to locate one of these. The trips are ususally very economical and provide a good base exposure.
    The Book is a very extent training book and is readily available online. Just search "Mountaineering, Freedom of the Hills"
    With some study and a bit of exposure it is not too hard to start identifying crevasses. They are almost always in a pattern on the hills and are somewhat predictable. The challenging part is in understanding the structural characteristics of snow. Many ( if not most) of them are just walked over via the snow that is bridging the gap. Being able to identify a viable bridge made of snow is somewhat tricky. Again it is a much better place for supervised instruction.

    Hope your trip comes together well. Anytime spent out on a tour like that is well worth it
     
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