One debunked photo shows a shark swimming on what is said to be a flooded road.
Forecasters expect the system to stay over water with 45 mph (72 kph) winds for 36 hours and then head back inland east of Houston sometime Wednesday. The system will then head north and lose its tropical strength.
Before then, up to 20 more inches (51 centimeters) of rain could fall, National Weather Service Director Louis Uccellini said Monday.
— With AP