As seen on Facebook:
This is going around via social media today. According to the caption, the photo was taken in Plaquemines Parish, Louisiana during flooding caused by Hurricane Isaac.
Not so. The original image dates from Aug. 2011 and was taken during a flood in Vladivostok, Russia. No hurricane. No alligator.

Comments
That is obviously NOT an alligator. It’s a Crocodile. I don’t think they have Croc’s in Louisiana.