Visible crew/equipment: You can see the string that pulls Bubba off the bike when Max shoots him. (01:19:41)
Visible crew/equipment: In the widescreen edition DVD, when Max's wife tugs at the chain on the back of the car after they have escaped the gang members, before she sees the ripped-off hand tied to it, you can see a crew member's hand holding the chain. (01:00:50)
Visible crew/equipment: After the bikers finish revving their engines (when they first arrive in town) there are a couple of close-ups of some of the bikers. One of the bikers starts unstrapping his headgear, as he does this four bright stagelights are reflected in the helmets visor.
Visible crew/equipment: When Goose is interrogating the stoned biker he turns around and says "Take your time Charlie, we've got plenty of it", when he turns you can see the feet of the camera operator reflected in his glasses. It cannot be the other policeman as he is in the other room.
Chosen answer: It was nuclear war. Tectonic plate movement could make ports dry and flood others. None of the movies ever goes into great detail about the apocalypse.
Grumpy Scot