Nearly two million flee Hurricane Gustav

The U.S. Coast Guard reported the first storm-related death in Florida, where a man fell overboard as his craft ran into heavy waves. Three others were believed to have died in hospital evacuations in Louisiana, Gov. Jindal said.

Katrina was a Category 3 when its 28-foot storm surge burst levees on August 29, 2005. New Orleans degenerated into chaos as stranded storm victims waited days for government rescue and law and order collapsed.

New Orleans resident Vanessa Jones, 50, said she had planned to stay but changed her mind after watching the news all night.

"I can't take a chance because so many people died in Katrina," Jones said as she prepared to board a bus headed to an unknown destination.

Thousands of people, still carrying emotional scars from Katrina, jammed highways out of New Orleans. The government lined up trains and hundreds of buses to evacuate 30,000 people who could not leave on their own and Nagin said 15,000 had been removed from the city, including hundreds in wheelchairs.

Residents boarded up the windows of their shops and homes before leaving town, while others hunkered down as "hold-outs" with stockpiled food, water and shotguns to ward off looters.

"I saw quite a bit of looting last time with Katrina, even 30 minutes after the winds had stopped," said construction contractor Norwood Thornton, who opted to stay behind to protect his home in New Orleans' historic Garden District.

Gustav weakened to a still dangerous Category 3 storm after it passed over Cuba. It killed at least 86 people in the Dominican Republic, Haiti and Jamaica.

But the latest warnings from the National Hurricane Center brought some relief with signs that the storm was weakening slightly and sucking up less power over the warm Gulf water that made Katrina an explosive Category 5 as it moved north.

Katrina and Hurricane Rita, which followed it three weeks later, wrecked more than 100 Gulf oil platforms, but Gustav could deal a harsher blow.

In a special trading session to accommodate the Labor Day holiday and the storm's impact, U.S. crude oil features on Sunday rose nearly $3 to over $118 per barrel.

"It remains likely that Gustav will prove to become a worst case scenario for the producing region and places the heart of the oil production region under a high risk of sustaining significant or major damage," said Planalytics analyst Jim Roullier.

As Gustav swirled through the Gulf, forecasters also kept an eye on Tropical Storm Hanna, which weakened slightly in the Atlantic about 140 miles north of Grand Turk Island.

(Additional reporting by Tom Brown in Miami and Bruce Nichols, Chris Baltimore and Erwin Seba in Houston; Writing by Jim Loney; Editing by Mary Milliken and Vicki Allen)