By HOLBROOK MOHR, AP ONLINE

GULFPORT, Miss. (AP) - Rescuers in boats and helicopters struggled to reach hundreds of wet and bedraggled victims of Hurricane Katrina on Tuesday as the scope of the disaster became clearer with every tale of misery. Mississippi's governor said the death toll in one county alone could be as high as 80.

In New Orleans, meanwhile, water began rising in the streets Tuesday morning, apparently because of a break on a levee along a canal leading to Lake Pontchartrain, prompting the evacuation of hotels and hospitals. New Orleans lies mostly below sea level and is protected by a network of pumps, canals and levees, but many of the pumps were not working Tuesday morning.

Officials began using helicopters to drop 3,000-pound sandbags into the breach, and expressed confidence the problem could be solved within hours.

All day, rescuers were also seen using helicopters to drop lifelines to victims and pluck them from the roofs of homes cut off by floodwaters.

``We know that last night we had over 300 folks that we could confirm were on tops of roofs and waiting for our assistance. We pushed hard all throughout the night. We hoisted over 100 folks last night just in the Mississippi area. Our crews over New Orleans probably did twice that,'' Capt. Dave Callahan of the Coast Guard in Mississippi said on ABC.

National Guardsmen brought in people from outlying areas to New Orleans' Superdome in the backs of big 2 1/2-ton Army trucks. Louisiana's wildlife enforcement department also brought people in on the backs of their pickups. Some were wet, some were in wheelchairs, some were holding babies and nothing else.

Nevertheless, it was clear the death toll would rise sharply, with one survivor after another telling of friends and loved ones who floated off or disappeared as the floodwaters rose around them.

``I talked with paramedics that are on the scene and the devastation is so great that they won't quit counting (bodies) for a while,'' said Mark Williams, operations supervisor for American Medicial Response, which operated ambulances along the Mississippi coast.

Along the coast, tree trunks, downed power lines and trees, and chunks of broken concrete in the streets prevented rescuers from reaching victims. Swirling water in many areas contained hidden dangers. Crews worked to clear highways. Along one Mississippi highway, motorists themselves used chainsaws to remove trees blocking the road.

Tens of thousands of people will need shelter for weeks if not months, said Mike Brown, director of the Federal Emergency Management Agency. And once the floodwaters go down, ``it's going to be incredibly dangerous'' because of structural damage to homes, diseases from animal carcasses and chemicals in homes, he said.

As of Monday night, more than 37,000 people were in American Red Cross shelters along the Gulf Coast, the organization reported.

Officials warned people against trying to return to their homes, saying that would only interfere with the rescue and recovery efforts.

Looting broke out in Biloxi and in New Orleans, in some cases in full view of police and National Guardsmen. On New Orleans' Canal Street, the main thoroughfare in the central business district, looters sloshed through hip-deep water and ripped open the steel gates on the front of several clothing and jewelry stores.

More than 1,600 Mississippi National Guardsmen were activated to help with the recovery, and the Alabama Guard sent 800 of its soldiers to Mississippi as well.

In New Orleans, a city of 480,000 that was mostly evacuated over the weekend as Katrina closed in, those who stayed behind faced another, delayed threat: rising water. Failed pumps and levees apparently sent water from Lake Pontchartrain coursing through the streets.

The rising water forced one New Orleans hospital to move patients to the Superdome, where some 10,000 people had taken shelter, and prompted the staff of New Orleans' Times-Picayune newspaper to abandon its offices, authorities said. Hotels were evacuated as well as the water kept rising.

Downtown streets that were relatively clear in the hours after the storm were filled with 1 to 1 1/2 feet of water Tuesday morning. Water was knee-deep around the Superdome. Canal Street was literally a canal. Water lapped at the edge of the French Quarter. Clumps of red ants floated in the gasoline-fouled waters downtown.

``It's a very slow rise, and it will remain so until we plug that breach. I think we can get it stabilized in a few hours,'' said Terry Ebbert, New Orleans' homeland security chief.

Gov. Haley Barbour of Mississippi said there were unconfirmed reports of up to 80 deaths in Harrison County - which includes devastated Gulfport and Biloxi - and the number was likely to rise. An untold number of people were also feared dead in Louisiana. At least five other deaths across the Gulf Coast were blamed on Katrina.

``We know that there is a lot of the coast that we have not been able to get to,'' Barbour said on NBC's ``Today Show.'' ``I hate to say it, but it looks like it is a very bad disaster in terms of human life.''

As for the death toll in Louisiana, Blanco said only: ``We have no counts whatsoever, but we know many lives have been lost.''

At the Superdome, someone died after plunging from an upper level of the stadium, Ebbert said. He said the person probably jumped.

The biggest known cluster of deaths was at the Quiet Water Beach apartments in Biloxi, a red-brick beachfront complex of about 100 units. Harrison County, Miss., emergency operations center spokesman Jim Pollard said about 30 people died there.

``This is our tsunami,'' Mayor A. J. Holloway of Biloxi, Miss., told The Biloxi Sun Herald.

Joy Schovest, 55, was in the apartment complex with her boyfriend, Joe Calvin, when the water began rising. They stayed despite a mandatory evacuation order.

``The water got higher and higher,'' she said, breaking into tears. ``It pushed all the doors open and we swam out. We grabbed a lady and pulled her out the window and then we swam with the current. It was terrifying. You should have seen the cars floating around us. We had to push them away when we were trying to swim.''

Teresa Kavanagh, 35, of Biloxi, shook her head is disbelief as she took photographs of the damage in her hometown.

``Total devastation. Apartment complexes are wiped clean. We're going to rebuild, but it's going to take long time. Houses that withstood Camille are nothing but slab now,'' she said. Hurricane Camille killed 256 people in Louisiana and Mississippi in 1969.

The hurricane knocked out power to more than 1 million people from Louisiana to the Florida Panhandle, and authorities said it could be two months before electricity is restored to everyone.

Oil prices jumped by more than $3 a barrel on Tuesday, climbing above $70 a barrel, amid uncertainty about the extent of the damage to the Gulf region's refineries and drilling platforms.

By midday Tuesday, Katrina was downgraded to a tropical depression, with winds around 35 mph. It was moving northeast through Tennessee at around 21 mph.

Forecasters said that as the storm moves north over the next few days, it could swamp the Tennessee and Ohio valleys with a potentially ruinous 8 inches or more of rain. On Monday, Katrina's remnants spun off tornadoes and other storms in Georgia that smashed dozens of buildings and were blamed for at least one death.