Most experts say the city's plans, if imperfect, are better thought out than those in other cities. They also say the city's mass transit network makes the plans for evacuating in advance of flooding or in the aftermath of isolated biological attacks more realistic than would be the case elsewhere.
These experts say there is no question that city officials have spent considerable time and money envisioning situations and developing strategies for dealing with them. But Katrina and the scenes that unfolded as Hurricane Rita howled toward Texas raised a question: Would it be possible to carry out a complete evacuation of New York City?
City officials do not pretend that it would be easy, or even doable. They say that very few situations would trigger such a necessity. Those situations are not hurricanes, but things like a nuclear event.
But even the "area evacuations" they envision for hurricanes-evacuations of zones they have already designated as likely to be flooded-could involve huge traffic jams. Given how many bridges and tunnels the city has, the jams in Houston could seem mild. And they say that moving hospital or nursing home patients completely out of the city would be an epic challenge.
Thus, after watching the disastrous, and in at least one instance deadly, backups in Houston, they have already tried to adjust their thinking about how to assist drivers who run out of gas. Yesterday, one official said, they worked out a plan to assign police escorts to gasoline trucks.
Officials are acutely aware that talking about an all-out evacuation is talking about something unprecedented in scope.
"If New York City had to be evacuated, that would become a national event," said Joseph F. Bruno, the city's emergency management commissioner. "The event would have to be so major, we'd call on federal assets almost immediately."
Officials like Mr. Bruno and experts who have studied emergency preparedness say New York is unique among cities for the potential usefulness of its transportation system. Its subways, buses and commuter trains carry eight million commuters a day as is, and people could get to neighboring states more easily by New Jersey Transit and PATH trains than by driving.
But Assemblyman Richard L. Brodsky and others have raised questions about the city's evacuation planning. Mr. Brodsky, a Westchester Democrat, takes issue with the city's estimates of how many evacuees it could handle in a hurricane.
He said that the city was prepared to handle a million evacuees and to provide shelter for 224,000 after a Category 4 hurricane. But he said that a 1993 Army Corps of Engineers study found that a less powerful Category 3 storm would create 2.5 million evacuees and the need to shelter as many as a million.
Mr. Bruno, who did not comment on Mr. Brodsky's characterization of the city's plans, said yesterday that, based on Houston's experience with Rita, he believes that both estimates are low. "We think more people will go" in an evacuation, he said.
"We do think that the earlier assumptions, a blasé New York approach, won't be there in light of Katrina and Rita," Mr. Bruno said. "People are going to act a little more frightened or be a little quicker to get out rather than say, 'I'm going to tough this out.' We saw too many images of that from New Orleans. The difference is New Orleans is below sea level and most of New York is not. We saw in Mississippi, which is not, that the land dried out quickly and people could get back. We'll be able to get people back."
Other experts question whether hurricane evacuations could be as limited in scope as the city envisions.
"We can't rest on a limited scenario, which is the sort of hurricane plan we have, where you just evacuate parts of the city from one portion of the city to other portions of the city," said Dr. Irwin Redlener, director of the National Center for Disaster Preparedness at the Mailman School of Public Health at Columbia University.
He also questioned how hospitals would evacuate patients. "To my knowledge, there are no plans that I would be comfortable with for evacuating major medical centers and nursing homes from the city," he said. "No hospital with 500 patients, including people on ventilators, people in intensive care, can get all those people out of the city on its own, without major help from outside."
Mr. Bruno said that the city's plan called for firefighters to go to hospitals and see what was needed. "We have them all mapped," he said. "If we see the possibility of an evacuation having to occur, the Fire Department will go out and communicate with each of them and say, 'What are your plans, how are you going to do it?"'
Mr. Brodsky based his study on parts of the city's plan. He said he had repeatedly asked for a complete copy of the plan but that the city had refused to release all of it at once, saying it was always "in flux."
Officials have said that a Category 3 hurricane could bring a 25-foot storm surge in the financial district, southern Brooklyn and eastern Staten Island and at Kennedy Airport. The city's plan calls for opening 23 "reception centers" and hundreds of shelters, mainly in schools. Evacuees would go to a reception center and be assigned to a shelter.
But city officials acknowledge that elements of an evacuation would have to be improvised.
The city's emergency operations center has room for representatives of more than 90 federal, state and city agencies. City officials say they have invited officials from surrounding counties and New Jersey.
In fact, Police Commissioner Raymond W. Kelly says that the city has two general evacuation plans, one for hurricanes and another to be put into effect in the event of a terrorist attack or other catastrophe.
The Police Department's role is a component of the overall plans, which have been prepared by Mr. Bruno's agency, the Office of Emergency Management.
Commissioner Kelly, in an interview yesterday, said that the hurricane plan had different contingencies for different hurricane levels. Under the hurricane plan, he said, the emergency management agency coordinates the response and the Police Department has its "core competencies": assisting in the evacuation, overseeing security in evacuated areas, and attending to traffic control and search and rescue operations.
The hurricane plan divides the city into three zones. Under the plan for an attack or other catastrophic event, the city would be divided into 151 sectors, each roughly equivalent in population and with some variation based on terrain and other particularities of individual neighborhoods.
In coordination with other agencies, the city would use trains, boats and city buses to move people out of the city along preset routes.
Mr. Kelly acknowledged that traffic, which sometimes seems to calcify during a normal commuter rush, would present a significant challenge.
But he declined to characterize the plan as unthinkable, saying he believed the size of the problem the Police Department could field would prevent the kind of paralysis that seemed to strike Houston.
Hanging over all this is the issue of how and when to inform the public, for no plan can succeed if residents are unaware of it. The city says it is prepared to spread the word , and that its efforts to do so include having Mr. Bruno appear on a Russian-language radio program (with a translator) to reach listeners in Brighton Beach, Brooklyn..
But others, Mr. Brodsky included, say that most residents have no idea of where to go or what to do in an evacuation, which is exactly what crippled New Orleans.