(CBS/AP) Hundreds, perhaps thousands, are dead since Hurricane Katrina hit New Orleans, according to the city's mayor.
"We know there is a significant number of dead bodies in the water," and others dead in attics, New Orleans Mayor C. Ray Nagin said Wednesday during an impromptu news conference at the Hyatt Hotel. Asked how many, he said: "Minimum, hundreds. Most likely, thousands."
Meanwhile, the U.S. government declared a public health emergency for the entire Gulf Coast Wednesday.
In addition to his ominous claim, Nagin added that it will be at least two or three months before the city has electricity. Restaurants won't be able to open and there won't be any commerce.
"This is the real deal. It's not living conditions," Nagin said.
The frightening estimate came as Army engineers struggled to plug New Orleans' breached levees with giant sandbags and concrete barriers, while conditions, health officials said, were "very dangerous" throughout the Gulf Coast.
Health and Human Services Secretary Michael Leavitt said his agency is concerned about potential disease outbreaks and was sending medical experts from the Centers for Disease Control and Prevention.
Leavitt urged residents of the coastal area to boil water and follow food safety precautions as well as to avoid situations that might lead to carbon monoxide poisoning from electricity generators.
Food, drinking water and shelter were in short supply in coastal Louisiana, Mississippi and Alabama.
There will be a "total evacuation of the city. We have to. The city will not be functional for two or three months," Nagin said.
Most of those refugees, 15,000 to 20,000 people, were in the Superdome, which had become hot and stuffy, with broken toilets and nowhere for anyone to bathe. "It can no longer operate as a shelter of last resort," the mayor said.
Nagin estimated 50,000 to 100,000 people remained in New Orleans. He said 14,000 to 15,000 a day could be evacuated.
The breaches in the levees were allowing water from Lake Pontchartrain to inundate sections of New Orleans. An estimated 80 percent of the city was under water, up to 20 feet deep in places, with miles and miles of homes swamped.
"This is the bowl effect that everyone has been talking about," Nagin told
CBS affiliate WWL. "Water is now going to fill the bowl on the east bank."
CBS News will present a half-hour prime-time special,
48 Hours: Katrina's Fury tonight at
8 p.m. EDT/PDT
The Army Corps of Engineers said it planned to use heavy-duty Chinook helicopters to drop 3,000-pound sandbags Wednesday into a 500-foot gap in one of the failed floodwalls. But the agency said it was having trouble getting the sandbags and dozens of 15-foot highway barriers to the site because the city's waterways were blocked by loose barges, boats and large debris.
At least 25,000 of Hurricane Katrina's refugees, a majority of them at the New Orleans Superdome, will travel in a 475-bus convoy to Houston starting Wednesday and will be sheltered at the 40-year-old Astrodome, which hasn't been used for professional sporting events in years.
"Everybody's scared, worried, desperate, and the living conditions there [in the Superdome] are horrible, so we're moving them out and trying to give them a little bit of ease," Blanco told
CBS News Early Show co-anchor Julie Chen (video).
"We've fought hurricanes before. You know, we think we are hurricane-smart and there's some normal things that go on during the aftermath of a serious hurricane, but this is not normal. This is past the normal thing that we normally have dealt with over the years," Blanco said.
"The people who have remained behind here in Orleans parish and in particular New Orleans are growing more and more desperate," reports
CBS News Correspondent Cami McCormick. "They cannot get out of the city. Many of them are running very low on supplies."
The sweltering city of 480,000 people — an estimated 80 percent of whom obeyed orders to evacuate as Katrina closed in over the weekend — also had no drinkable water, the electricity could be out for weeks, and looters were ransacking stores around town.
In other developments:
The U.S. Navy is sending four ships carrying water and other supplies, along with the hospital ship USNS Comfort, search helicopters and eight swift-water rescue teams.
Medical disaster teams and Red Cross workers from across the country converged on the devastated Gulf Coast region. The Red Cross reported it had about 40,000 people in 200 shelters across the area.
CBS News reports that the Pentagon said 65 percent of the Louisiana National Guard is available and 60 percent of the Mississippi force is available. Both Louisiana and Mississippi have one brigade each in Iraq.
The extensive damage caused by Hurricane Katrina to oil platforms and refineries in the Gulf of Mexico sent crude oil prices surging back above $70 a barrel Wednesday. But prices turned lower after Energy Secretary Samuel W. Bodman said the government would release oil from its reserves.
At the same time, sections of Interstate 10, the only major freeway leading into New Orleans from the east, lay shattered, dozens of huge slabs of concrete floating in the floodwaters. I-10 is the only route for commercial trucking across southern Louisiana.
There could be an effect on agribusiness, reports CBS News Correspondent Dan Raviv: Cotton and sugarcane crops were flattened in the hurricane zone, and U.S. exports of corn and soybeans need to get through New Orleans in about six weeks — if the port is reopened.
