HOUSTON (Reuters) – Energy producers and communities along the U.S. Gulf Coast organized evacuations of residents and offshore workers on Sunday as they prepared for the second hurricane strike in less than a month.

Tropical Storm Sally strengthened as it crept up the warm waters of the U.S. Gulf of Mexico on Sunday, carrying winds that could reach 100 mile per hour (160 kph) ahead of landfall on Tuesday, forecasters said.

Sally was upgraded to an “extremely dangerous” potential Category 2 hurricane. It was about 300 miles (482 km) from the mouth of the Mississippi River and moving at 13 mph, according to the U.S. National Hurricane Center. At 8 a.m. EDT, its sustained winds had increased to 50 mph, the NHC said.

Chevron Corp. (NYSE:) and Murphy Oil Corp (NYSE:) on Saturday began evacuations from offshore production platforms, spokespeople said. Chevron’s Pascagoula, Mississippi, refinery was implementing storm preparedness procedures, the company said.

Other oil producers with drilling rigs and platforms in the area said they were monitoring the storm and prepared to take action as needed.

U.S. Gulf of Mexico offshore oil production provides about 17% of oil and 5% of U.S. production. As much as 1.5 million barrels per day of oil output was shut last month as Hurricane Laura tore through the Gulf of Mexico.

Louisiana on Saturday declared a state of emergency and the city of New Orleans ordered a Sunday 6 p.m. CDT evacuation for residents outside the city’s protective levees. Coastal Grand Isle also issued its third evacuation since July.