The ash and boulders had been building up since an eruption in July, high on the slopes of the Mayon volcano. Typhoon Durian's blasts of wind and drenching rain raked it all down in a deadly black wall of debris.

For nearly three hours Thursday afternoon, mudslides ripped through Mayon's gullies, uprooting trees, flattening houses and engulfing people. Entire hamlets were swamped in Mayon, on northern Luzon island.

Some 208 people were killed — most in mudslides on Mayon — and 261 were missing, the national Office of Civil Defense reported late Friday. Another 82 were injured.

With power and phone lines down, it took until Friday morning, when the first flights managed to survey the area, for the scope of the devastation to emerge.

Visit FOXNews.com's Natural Disaster Center for complete coverage.

"The disaster covered almost every corner of this province — rampaging floods, falling trees, damaged houses," said Fernando Gonzalez, governor of Albay province, the site of all but a few of the deaths.

Pope Benedict XVI, saddened by the "tragic loss of life," was praying for the victims, rescue workers and others providing assistance, the Vatican said.

"Our rescue teams are overstretched rescuing people on rooftops," said Glen Rabonza, the Civil Defense head, after officials briefed President Gloria Macapagal Arroyo on the disaster and the difficulties of getting to survivors stranded by seas of black mud.

Bodies were wrapped in blankets and slung on bamboo poles to be carried to trucks, then covered with coconut leaves and transferred to makeshift morgues.

"It's terrible. We now call this place a black desert," Noel Rosal, mayor of Legazpi city, Albay province's capital, said after visiting one stricken village.

Rosal said three of the five communities comprising the village of 1,400 people had been "wiped out" with only the roofs of several houses jutting out of the debris. He said people claimed some of the boulders were as big as cars and red hot, suggesting fresh lava from 8,077-foot Mayon.

His own residence was under water that rose "higher than a person" in a flash flood.

"I was almost a goner. I had to swim," Rosal said.

Mayon, a popular tourist attraction because of its nearly perfect conical shape, is one of the Philippines' 22 active volcanos. It erupted in July, depositing millions of tons of rocks and volcanic ash on its slopes, and has continued to rumble since then. Rains from succeeding typhoons may have loosened the materials.

Villagers have lived with the threat of a Mayon eruption — the most violent one killed more than 1,200 people in 1814 — but say they never heard of debris being washed so far down or so violently.

Typhoon Durian blasted ashore with gusts of up to 165 mph, running head-on into Mayon, 210 miles southeast of Manila on Luzon island.

"When the water suddenly rose, we ran for our lives," said Lydia Buevos, 58, who returned with her husband and children Friday to see their hut gone. Holding a pair of rubber sandals — the only possession she was able to save — she said she lost three relatives to the storm.

"It happened very rapidly and many people did not expect this because they haven't experienced mud flows in those areas before," Gonzalez said. "By the time they wanted to move, the rampaging mud flows were upon them."

The typhoon weakened Friday as it moved northward, with sustained winds of 94 mph and gusts of up to 116 mph as it headed toward the South China Sea.

Cars zigzagged on the road to the affected area to avoid uprooted trees and toppled utility posts Friday. Steel pylons had been bent down by the wind, and power cables lay scattered about like strands of spaghetti.

With the sky surprisingly blue already, people dug foundations for new homes, hammering tin sheets onto leaking roofs and drying pillows, mattresses and clothes in the sun.

Durian was the fourth "super typhoon" to hit the Philippines in as many months. In late September, Typhoon Xangsane left 230 people dead and missing in and around Manila. Typhoon Cimaron killed 19 people and injured 58 others last month, and earlier this month, Chebi sliced through the central Luzon region, killing one.

About 20 typhoons and tropical storms hit the Philippines each year.

Visit FOXNews.com's Natural Disaster Center for complete coverage.