And, as happened in New Orleans, there would be no place for the dead.
"If you look at the expected number of deaths that could occur in cities across the United States, we are wholly unprepared to process those bodies in a dignified and respectful way," asserts Michael Osterholm, director of the Center for Infectious Disease Research and Policy. "We will run out of caskets literally within days."
The prospects have become so bleak that in planning meetings held in New York City, veteran emergency responders have walked away.
"They just don't know how we're going to get through," says Osterholm of those responders. "If we have a repeat of the 1918 life experience, I can't imagine anything to be closer to a living hell than that experience of 12 to 24 months of pandemic influenza."
If the flu does strike, victims at first would not know if it is the kind of easily treated flu that comes every year or the killer flu, known as H5N1.
The man in charge of making sure Americans are prepared in the event of a killer flu epidemic is the secretary of Health and Human Services.
"We would do all we could to quarantine," says Secretary Michael Leavitt. "It's not a happy thought. It's something that keeps the president of the United States awake. It keeps me awake."
The preparedness plan calls for Leavitt to run operations out of a crisis room in Washington.
When pressed as to how ready the country actually is, Leavitt replied, "Not as prepared as we need to be. We're better prepared than we were yesterday; we'll be better prepared tomorrow than we are today."
The draft report of the federal government's emergency plan, obtained and examined by ABC News' "Primetime," predicts as many as 200,000 Americans will die within a few months. This is considered a conservative estimate.
"The first thing is everybody in America's going to say, 'Where's the vaccine?' And they're going to find out that it's really darned hard to make a vaccine. It takes a really long time," said Garrett of the Council on Foreign Relations.
In fact, the draft report says it will not be until six months after the first outbreak that any vaccine will be available, and then only in a limited supply.
"I imagine that not a lot of poor people will get vaccinated," Garrett says. "If you think about New Orleans, this is a similar situation."
While there is no vaccine to stop the flu, there is one medicine to treat it. Called Tamiflu, it is made by the Roche pharmaceutical company in Switzerland. Roche has been selling Tamiflu for years.
Only recently, however, did scientists learn of its potential to work against the killer flu, H5N1. That has since created a huge demand and a critical shortage.
"All of the wealthiest countries in the world are trying to purchase stockpiles of Tamiflu," says Garrett. "Our current stockpile is around 2.5 million courses of treatment."
According to Leavitt, that is a long way from the country's ideal stockpile. "Our objective is to have 20 million doses of Tamiflu or enough for 20 million people," he says.
He later admitted that only 2 million are currently on hand, but asserted that no other country is in a better position.
Officials in Australia, however, have 3.5 million courses of treatment, and in Great Britain, officials say they have ordered enough to cover a quarter of their population.