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?