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, uprooted trees, flattened houses and engulfed 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. 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.
"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.
"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 that some 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.
Typhoon Durian blasted ashore with gusts of up to 165 mph, running into Mayon, 210 miles southeast of Manila.
"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.