Tropical Storm Isaac closed in on the U.S. Gulf Coast Monday, triggering evacuation orders in some areas and disrupting offshore oil production as it threatened to make landfall between Florida and Louisiana as a full-blown hurricane.
The wide, slow-moving storm swiped south Florida on Sunday and strengthened over the warm Gulf waters. It was expected to reach land late today or early Wednesday, the anniversary of devastating Hurricane Katrina seven years ago.
The U.S. National Hurricane Center warned the storm could buffet towns and cities in at least three U.S. states near the shoreline and flood the northern Gulf Coast with a storm surge of up to 3.6 metres.
Isaac was forecast to strengthen into a Category 1 hurricane, the lowest on the five-step Saffir-Simpson scale of hurricane intensity, with top winds of 153 km/h before making landfall and moving over the Gulf Coast.
The storm could take direct aim at New Orleans, which is still struggling to fully recover from Katrina, which swept across the city on Aug. 29, 2005, killing more than 1,800 people and causing billions of dollars of damage along the coast.
"I want to tell everybody now that I believe that we will be OK," New Orleans Mayor Mitch Landrieu said.
The storm was more than 645 km wide. Craig Fugate, director of the Federal Emergency Management Agency, said the worst effects may be in Mississippi and Alabama.
The governors of Louisiana, Mississippi and Alabama declared states of emergency, and mandatory evacuation orders went into effect for up to 10,000 residents of Mobile, Alabama.
President Barack Obama approved Louisiana's request for a federal disaster declaration, Gov. Bobby Jindal said.