SuPrBuGmAn
Contributor
If You had an actual "slide" of sand (new material that has not been disturbed before) you would think that it would take some time to have the natural flow remove the fines and clear up the viz. I can see a shift of sand in a restriction depending on flow volume. If he went through a narrow passage and the sand shifted, closing out his ability to return, that would seem more probable. I am not familier with the caves you guys dive in, but wouldn't this shift of sand in restricted areas either fill in the area or flush it out depending on flow? It would then be possible that if he was behind a restriction that blocked his exit that when the flow increases during this winter that the restriction would open back up again and possibly release him back into the main part of the system.
Its a continual effect. The flow builds the sand up into a slide. Eventually, it will slide naturally, sometimes its disturbed and slides prematurely. Then the process repeats, infinately.
I don't think he's trapped behind some restriction to be honest... if anything, he's under it. Thats just my opinion, if he's in the cave at all, which I'm certainly not 100% on...
If he's under sand, he'll turn up eventually :/