According to the parish Web site, even Ike's passing the Louisiana coast is enough to put Lafourche in danger of a storm surge, and the parish is under a state of emergency:
* MANDATORY EVACUATION: all areas south of the Leon Theriot Floodgates in Golden Meadow and the community of Pointe-Aux-Chenes.
* This is due to lingering flood waters expected due to Hurricane Ike.
* A State of Emergency has been declared for Lafourche Parish.
Current call is still for landfall on the central Texas coast. According to Jeff Masters at Weather Underground:
The appearance of Ike on infrared satellite loops is similar to Hurricane Wilma during its rapid intensification phase, when Wilma became the strongest hurricane on record. Like Wilma, Ike has a very tiny "pinhole" eye, but the storm is huge in size. Ike has a long way to go to match Wilma, but I expect Ike will be at least a Category 3 hurricane by morning, and probably a Category 4.
Ike is almost as large as Katrina was, and this large wind field is already beginning to pile up a formidable storm surge. Tides are running 2-4 feet above normal along the Gulf Coast from Louisiana to the west coast of Florida. Tides have risen one foot above normal in Galveston already, too. The water level will continue to rise as Ike approaches Texas, and NOAA's experimental storm surge forecast is calling for a 10% chance that the storm tide from Ike will reach 10-12 feet at Galveston, and 18-21 feet on the south and east sides of Houston.
Best wishes to the Houston/Galveston area if large-scale evacuations become necessary.