I may be crazy, but I'm actually glad you brought up Swamp People. Since this nighttime search started I've been thinking "Swamp People." Those guys go out at night, on the swamps, all the time. The water is calm then. You can see it via the footage they capture when they're out there, and unless there's a storm brewing it's common sense. If the current was too much for the divers before, they've likely been monitoring it for when it wasn't. There is a storm projected tomorrow (weatherman's reputation disputed), calm before the storm perhaps?
That original search may have been called off to the rough current conditions that have been mentioned (is this rumor, or fact?), and now they're trying to get it in in calm waters before the risk of rain washing evidence away.