Hundreds of thousands of people in the US states of Louisiana and Mississippi are fleeing ahead of the expected arrival of Hurricane Katrina in the region.
The hurricane has now grown into a Category Five storm with winds of over 280kph.
Forecasters have warned that a hurricane of this size is capable of causing catastrophic damage.
Mandatory evacuations are underway in the city of New Orleans. The city, with a population of about 1.4 million people, is about two metres below sea level.
Forecasters say the city could be in the eye of the storm when Katrina hits.
Hotels and buildings in the historic French quarter have been boarded up and largely deserted. The city's mayor appeared on local television to urge residents to take the threat seriously and prepare to go.
Katrina is the sixth hurricane to hit the Florida coastline since last August and has already killed seven people.
US President George Bush has declared states of emergency in Louisiana and Mississippi, a measure that allows federal aid to be deployed.
Katrina is the 11th named Atlantic storm this year and among the most powerful Atlantic hurricanes on record.
Records going back to 1851 show that only three Category Five hurricanes have hit the United States in over 150 years.
The last such hurricane to strike the area was Hurricane Camille in 1969. Camille - which just missed New Orleans - devastated parts of Mississippi, Louisiana and Alabama and killed more than 250 people.
