... and immensely challenging environment (surely the most challenging for any audio pro?).
Actually no, I have seen worse. I was once on set at Pinewood Studios, they have a huge tank and blue screen in which was a mock-up of a ship and they were filming a storm scene. To get the wind and rain effect they were simultaneously using 2 x 9ft fans and a small jet engine. One of the hurdles to overcome was that no matter how loud the director screamed, the actors could not hear him shout "Action"! The PSM tried to record some dialogue, just to use as a guide in post, but the result was unusable even as a guide, so he powered down and we went for coffee! It was always planned that this scene would be ADR/dubbed.
I've been on location shoots a few times where recording usable production sound was not possible (even with a highly experienced/equipped professional production sound team) and the whole scene had to be ADR'ed. In documentary workflows ADR is very rarely an option, due to relatively small audio post budgets, unscripted dialogue, subjects who are not available for ADR and/or have no training/experience in recording ADR. I am presuming that the OP's situation is the same as the usual documentary workflow and apart from some narration/VO's, there won't be any dubbing/ADR during post-production. The required standards/expectations for sound is much lower in the documentary world than in the TV or theatrical drama world but even so, the standards are still relatively high compared to what most micro/no budget indie filmmakers are used to. Not least because of the requirement for M&E mixes if you want to be able to sell to networks and/or non-English speaking markets. A highly experienced and well equipped professional PSM is a minimum requirement if you want to end up with something saleable beyond self distribution, VOD or the small cable channels.
As far as naturally occurring environments are concerned though you are probably right, I can't think of anything much more challenging except for some naturally occurring events such as thunder storms, hurricanes, tornadoes, etc.
G
