[JURIST] Mayor Ray Nagin ordered the entire US city of New Orleans (population 484,674) evacuated Sunday in advance of the anticipated Gulf Coast landfall Monday morning of Hurricane Katrina [Wikipedia backgrounder], currently described by the National Weather Service as a "potentially catastrophic" Category-5 storm packing winds of nearly 175 miles per hour [NWS advisory; NWS Saffir-Simpson Hurricane Scale backgrounder]. New Orleans has long been considered vulnerable to hurricanes [Weather Channel backgrounder] and major storms because it's an average of six feet below sea level, and could be almost completely flooded by a storm surge topping the levees that protect it. The Mayor's mandatory evacuation order, issued through the Civil District Court for the Parish of Orleans, declares:

1. A mandatory evacuation order is hereby called for all of the Parish of Orleans, with only the following exceptions: essential personnel of the United States of America, State of Louisiana and City of New Orleans; essential personnel of regulated utilities and mass transportation services; essential personnel of hospitals and their patients; essential personnel of the media; essential personnel of the Orleans Parish Criminal Sheriff's Office and its inmates and essential personnel of operating hotels and their patrons. Unless covered by one of the aforementioned exceptions, every person is hereby ordered to immediately evacuate the City of New Orleans or, if no other alternative is available, to immediately move to one of the facilities within the City that will be designated as refuges of last resort.

2. In order to effectuate the mandatory evacuation, at the direction of the Mayor, the Chief Administrative Officer, the Director of Homeland Security for the City of New Orleans or any member of the New Orleans Police Department, the City may commandeer any private property, including, but not limited to, buildings that may be designated as refuges of last resort and vehicles that may be used to transport people out the area.

Read the full text of the order. The Mayor's Office has also posted a list of designated shelters, with the Louisiana Superdome [corporate website] having been designated a "shelter of last resort" for those who cannot leave. In 1998, Hurricane Georges [Wikipedia backgrounder] prompted a voluntary evacuation of an estimated 60 percent of the New Orleans population, the largest evacuation in US history to that the time according to the National Weather Service. A Category-2 storm with 110 mile-per-hour winds, Georges landed east of the city in Biloxi, Mississippi. Only three Category-5 hurricanes have ever hit the United States [NWS factsheet]: Hurricane Camille in 1969, Hurricane Andrew in 1992, and an unnamed hurricane that hit Florida in 1935. If Katrina maintains strength and pressure cited in weather reports Sunday afternoon, it could become the most powerful hurricane to hit the US in recorded history.

CBS WWLTV in New Orleans has more, and provides continuing coverage [including live video] of the latest evacuation and hurricane developments. The Louisiana Department of Homeland Security and Emergency Preparedness offers additional information on hurricane preparations. President Bush has urged residents to move to safe ground and has already declared a state of emergency for Louisiana [White House text]. AP has more.