MANILA AND SEOUL — Thousands of Filipinos were marooned on rooftops Friday, and officials released water from at least one large dam to keep it from collapsing as heavy rain from Tropical Depression Parma pummeled the archipelago.
Hundreds of people were reported killed by flooding and landslides, bringing the death toll from two storms in the last 10 days to more than 500, Philippine authorities said.
Officials said 60% of Pangasinan province, about 110 miles north of Manila, was submerged. Strong winds and rain hampered rescue efforts, grounding military helicopters and lifeboats. Officials received frantic text messages from residents begging to be rescued from the rooftops of malls and houses. One dam, weakened by pounding rains, collapsed.
"Thirty of Pangasinan's 48 towns are now underwater," said Gov. Amado T. Espino Jr. "I am appealing for 10-wheeler trucks, helicopters, rubber boats and amphibious vehicles."
Attempting to prevent a second dam collapse, officials released a wall of water from the San Roque dam on the Agno River, which flows through 18 communities in the province.
Major highways north of Manila were submerged, isolating the northeastern section of Luzon island as well.
The National Disaster Coordinating Council said that a million people had been displaced by Parma, with about 40,000 seeking refuge at 162 evacuation centers.
"The water is so high and it's still rising," said Deborah Castillo, a spokeswoman for the mayor of Santa Barbara, a town of 80,000 north of Manila. "The road is gone. There are so many towns like ours underwater that the regional government doesn't have enough usable lifeboats to reach all the people who are begging to be saved."
Parma, which still was lingering off the Philippines' northeastern coast, is the second major storm to hit in two weeks. The storm slammed the nation days after Tropical Storm Ketsana killed about 300 people in metropolitan Manila and surrounding provinces and caused $100 million in damage.
Parma has baffled weather forecasters, making landfall three times in eight days. It is expected to move away from the Philippines in the coming days.
"This is the first typhoon in our history to behave in this strange manner," said Nathaniel Cruz, a weather bureau spokesman in Manila.
Meanwhile, the high waters from Ketsana still have not subsided. Officials in Manila worry that rivers now carrying raw sewage and bodies present a serious health risk.
Marooned residents north of Manila took center stage Friday as officials were forced to divert helicopters to deal with new flooding.
In San Fabian, 20 houses were washed away after the Binday Dam failed. Officials there said they had observed cracks in the dam days ago but could not repair them because of the rain.
At least 100 people have died in several landslides in nearby Benguet province, a local official said.
The southern Philippines also was hit by flooding. In Mindanao, military rescuers said 20 families lost their houses to rising floodwaters. A mosque was destroyed when huge waves hit the area.
But Pangasinan province bore the brunt of Parma's wrath. Philippine navy spokesman Lt. Col. Edgard Arevalo said in a radio interview that the flooding situation not only in Pangasinan but also in the rest of northern Luzon island was "turning from bad to worse."
Philippine news reports said coast guard helicopters left Manila loaded with dinghies to be dropped to waiting rescue teams there. Officials gave priority to people stranded atop buses at two transportation terminals.
U.S. military personnel were helping in the rescue operations. Philippine Defense Secretary Gilberto Teodoro asked Friday that the U.S. dock landing ship Harpers Ferry join in rescue efforts in Pangasinan province, Philippine news reports said. U.S. military helicopters already were being used in metropolitan Manila.
Vanzi is a special correspondent. Special correspondent Al Jacinto in Zamboanga City contributed to this report.