Briton Martin Laird and Canadian Nick Taylor mixed 11 birdies with three bogies for a 10-under round of 62 and a share of second place with American Brian Gay and Slovak Rory Sabbatini.
Gay and Sabbatini's round was suspended for darkness after the 14th hole, where they had just made a ninth straight birdie.
They were far from alone in finishing early, with only eight teams able to complete their rounds at the course on the Mississippi River, which shares space with resident alligators.
The shot of the day belonged to Kevin Kisner, who had his first hole-in-one at a PGA Tour event on the 201-yard, par-three third as he and fellow American Scott Brown moved into a tie for sixth.
The weather is forecast to improve on Friday and through the weekend at the event, which features 80 two-player teams playing fourball in the first and third rounds and foursomes in the second and a final rounds.
(Reporting by Rory Carroll; Editing by Ian Ransom)
