Thousands fleeing New Orleans before Gustav

By Tim Gaynor and Kathy Finn

NEW ORLEANS (Reuters) - Thousands of people fled New Orleans on Saturday ahead of a likely evacuation order as Hurricane Gustav took aim at the Louisiana coast, reviving traumatic memories of Hurricane Katrina.

City Mayor Ray Nagin said if Gustav -- now a Category 4 storm with 150-mph (240-kph) winds -- holds to its current course, a city evacuation could start early on Sunday.

But one day after the third anniversary of Katrina, many already had decided to abandon the city, much of which lies below sea level.

Gustav was headed toward the Cuban mainland on Saturday and could hit the U.S. Gulf Coast as a Category 4 storm on the five-stage Saffir-Simpson scale of hurricane intensity, the U.S. National Hurricane Center said.

It could reach the central Louisiana coast by late Monday or early Tuesday.

In the Lower Ninth Ward, plunged under water by Katrina's flood waters, hundreds of residents packed belongings into cars and trucks and left. Some had returned home only a few months ago after fleeing Katrina.

"After Katrina, you've got to leave," said Ruby Hall, a longtime resident, pointing to the place on the timber frame of the porch where Katrina's waters rose. "I'm not going to chance it, not with my grandchild."

Katrina's massive storm surge broke through protective levees on August 29, 2005, and flooded 80 percent of the city. New Orleans degenerated into chaos as stranded storm victims waited days for rescue.