Hundreds of thousands of Mexicans fled a flooded region of the swampy Gulf coast Friday, jumping from rooftops into rescue helicopters, scrambling into boats or swimming out through the murky brown water. President Felipe Calderon, flying overhead, called it one of Mexico's worst recent natural disasters.

A week of heavy rain caused rivers to overflow, drowning at least 70 percent of the swampy, oil-rich state of Tabasco. Much of the state capital, Villahermosa, looked like New Orleans after Hurricane Katrina, with murky water reaching to rooftops and desperate people waiting to be rescued, and officials warned that waterborne disease outbreaks were possible.

At least one death was reported and nearly all services, including drinking water and public transportation, were shut down as an estimated 900,000 people had their homes flooded, damaged or cut off.

A 10-inch natural gas pipeline sprung a leak after flooding apparently washed away soil underneath it, but it was unclear if other facilities operated by the state-run Petroleos Mexicanos had suffered damage.

Rain gave way to sunshine Friday but forecasters predicted more precipitation in the coming days. The flooding was not related to Tropical Storm Noel, which pounded the Caribbean.

Tabasco state floods every year around this time. Workers tried to protect Villahermosa's famous Olmec statues by placing sandbag collars around their enormous stone heads, and built sandbag walls to hold the Grijalva river as it flows through the state capital.

But the quickly rising waters surprised even flood-weary residents, forcing soldiers to evacuate the historic city center, and the dikes failed Thursday night, flooding the city's bus station and open-air market.

Tens of thousands of people were still stranded Friday on rooftops or inside the upper floors of their homes. Rescue workers used tractors, helicopters, jet skis and boats to ferry people to safety, while others swam through poisonous-snake-infested waters to reach higher ground.

Calderon was meeting with state officials, flying over the affected areas and visiting a makeshift shelter. The extent of the flooding was clearer from the sky — Tabasco state seemed like an inland sea with only rooftops and treetops protruding from the water.

In a televised address late Thursday, the president called on Mexicans to donate emergency supplies as the government trucked in bottled water, food and clothing.

"The situation is extraordinarily grave. This is one of the worst natural disasters in the history of the country," Calderon said.

Mexico rallied around the disaster, with people across the country contributing money and supplies. Mexican television stations dedicated entire newscasts to the flooding. Morning entertainment shows switched from yoga and home improvement to calls for aid. And even though Friday was the national Day of the Dead holiday, banks remained open to accept donations for flood victims.

Food and clean drinking water were extremely scarce, and federal Deputy Health Secretary Mauricio Hernandez warned against outbreaks of cholera and other waterborne diseases.

"With so many people packed together there is a chance that infectious diseases could spread," Hernandez said.

Officials tested for 600 suspected cases of cholera, but none was positive, he said. The waterborne sickness, which is often fatal, has not been reported in Mexico for at least six years.

The government also sent 20,000 Hepatitis A vaccinations and were giving booster shots to children to prevent outbreaks, Hernandez said.

But medical care was difficult because at least 50 of the state's hospitals and medical centers flooded.

Safe refuges were scarce: Parking garages and any other dry structures were converted into temporary shelters.

Guadalupe de la Cruz, a receptionist at the Hotel Calinda Viva Villahermosa, located in an elevated area of the city, said the hotel's meeting rooms are being used as shelters for employees' families. De la Cruz said the 240-room hotel was completely booked, mostly by people who had fled their homes.

Many victims were being transferred to nearby cities unaffected by the floods. Highways that weren't covered with water were packed with residents fleeing in cars and on foot.

Villahermosa resident Mauricio Hernandez, 27, who is not related to the federal official, paid a taxi to bring him to Cardenas, a city 30 miles east of Villahermosa. From there, Hernandez planned to hop a bus to the port city of Coatzacoalcos.

"We are leaving because we cannot live like this," he said. "We don't have any water, and the shelters are full. Where are we going to go?"

State officials sent 50 buses to a museum in the capital where hundreds gathered.

"We wanted to stay in the city but it is no longer possible," said Jorge Rodriguez, 43. "We have lost everything."