Realizing that no Federal or local agency will be able to do much of anything when Hurricane Gustav reaches New Orleans, Mayor Ray Nagin has initiated the mandatory evacuation of half the city's coastal parishes today. And he when he says get out, he means it. There will be no emergency centers and the Superdome will not be a scene of mass chaos and tragedy this time around-because it's going to be closed. More on the evacuation, and video of Nagin's scary-ass warning, after the jump.

Coastal parishes in New Orleans began the first mandatory evacuations at noon (1700 GMT). Police were set to enforce a nightly curfew and cordon off areas under evacuation order, so that no one could enter.

Residents were warned that the city would not have emergency shelters, and that gathering areas such as the Superdome and bus terminal — scenes of chaos and violence after Katrina — would be closed.

As some residents boarded up windows and piled sandbags to build temporary levees, others boarded buses while shoppers crowded grocery stores to grab provisions for the weekend. Many service stations were already out of fuel.

"It's better organized this time," said Naomi Brown as she unpacked a shop's last box of batteries.

"We are getting information earlier, buses are coming, they got it a whole lot better this time. During Katrina, not one thing was organized — it was a state of panic and havoc."

The overall population of greater New Orleans is estimated at more than one million people, about 80 percent of the pre-Katrina population. Saturday's mandatory evacuation orders affected more than half of New Orleans' seven parishes.

The New Orleans airport said it would shut down Sunday evening, and area hotels advised customers to leave town.

Voluntary and assisted evacuations began Friday, but not all residents were eager to pack up and leave.

"I'm supposed to be leaving but I keep waiting just a little longer to see what the storm is going to do. I know it's a risk," New Orleans resident Sheile Robertson told AFP.

She said she escaped a day before Katrina struck, destroying her home, and now lives in an apartment with a half dozen people. [AFP]