Hurricane Gustav is expected to make landfall on the US Gulf coast today, three years after Katrina devastated New Orleans.
Hundreds of thousands of residents have fled the city after its mayor warned “the storm of the century” was coming and it was “time to be scared”.
President George Bush warned America of the “dangerous” threat posed by the storm and the Republican Party’s national convention was essentially suspended.
Mr Bush, who was severely criticised for his administration’s poor response to the Katrina disaster, urged residents on the US Gulf coast to heed local warnings and added: “Know that the American people stand with you and we will face this emergency together.”
Roads out of New Orleans were crammed with traffic and authorities have been trying to help evacuate anyone who cannot get themselves out.
Gustav, which is set to hit land later today, has already left a trail of death and destruction in its wake, killing more than 80 people across the Caribbean.
Speaking at the headquarters of the Federal Emergency Management Agency (Fema) yesterday, the president said governors and local leaders across the Gulf coast were “taking this storm very seriously and preparing pro-actively”.
Gustav was “dangerous” and posed a “serious risk of significant flooding”, he said.
“This nation has come to know the strong and resilient spirit of the people of the Gulf Coast. They’ve made it through great challenges in the past and they’re going to make it through this one, as well.”
He went on: “While the Army Corps of Engineers assure me the levees are stronger than they have ever been, people across the Gulf coast, especially in New Orleans, need to understand that in a storm of this size there’s serious risk of significant flooding.
“My message to the people of the Gulf coast is: this storm is dangerous. There’s a real possibility of flooding, a storm surge and high winds.”
He warned residents: “Do not put yourself in harm’s way or make rescue workers take unnecessary risks...And know that the American people stand with you and we will face this emergency together.”
He said teams of emergency managers, doctors, ambulances and search and rescue teams were ready and “millions of meals and millions of litres of water” had been pre-staged.
Mr Bush said Fema was working with governors to identify out-of-state shelters for people in the path of the storm and announced plans to visit emergency workers and evacuees in Texas later today
He was widely criticised in the wake of Katrina, which killed more than 1,800 people in US coastal areas, for a slow, apparently casual, approach to the disaster and the relief effort.
Yesterday, New Orleans mayor Ray Nagin imposed a dawn-to-dusk curfew from sunset last night as Gustav approaches and said the storm would be “big and ugly”.
The hurricane dropped from a Category 4 to a Category 3 storm on Sunday morning, but forecasters warned it could gain strength from the Gulf’s warm waters before making landfall as early as today.
Looting, one of the major problems in the wake of Katrina three years ago, would not be tolerated, Mr Nagin said.
“Looters will go directly to jail,” he said. “You will not get a pass this time. You will not have a temporary stay in the city. You will go directly to the Big House.”
He said looters would be put directly into the general population of one of the city’s toughest prisons.
Earlier, he told residents: “You need to be scared; you need to get your butts out of New Orleans now. This is the mother of all storms. I am not sure we have seen anything like it.”
He said staying behind would be one of the biggest mistakes of their lives.
“If you are stubborn enough, if you are not taking this as seriously as we need you to take it, and if you decide to stay; you are on your own,” he said.
“Anyone who decides to stay, I’ll say it like I said it before Katrina: make sure you have an axe, because you will be carving your way, or busting your way out of your attic to get on your roof with waters that you will be surrounded with in this event.”
Homeland Security Secretary Michael Chertoff headed to the region and said the main evacuation was going well but some people seemed determined to ride out the storm.
“That strikes me as exceptionally foolish,” he said.
Mr Chertoff also appealed for the “maximum level of co-operation from the individual public”.
The US authorities’ actions will be closely scrutinised after what was widely seen as a series of catastrophic failures in its slow and inadequate response to Katrina.
After Katrina hit land on August 29, 2005, three-quarters of the city was flooded after the storm surge breached its protective levees and more than 1,800 people were killed in US coastal areas.