Updated

MOUNT MERAPI, Indonesia -- The tiny hospital at the foot of Mount Merapi struggled Saturday to cope with victims brought in after the fiery volcano unleashed its most powerful eruption in a century -- some with burns covering 95 percent of their body.

The only sign of life in one man, who's eyes were milky gray in color and never blinked, was the shallow rising and falling of his chest. Others, their lungs choked with abrasive volcanic ash, struggled to breathe.

Indonesia's most volatile mountain unleashed a surge of searing gas, rocks and debris Friday that raced down its slopes at highway speeds, torching houses and trees and incinerating villagers caught in its path.

With more than 90 killed, many of them after succumbing to their injuries, it was Merapi's deadliest day in decades, but Sigit Priohutomo, who works at Sardjito hospital, predicted the toll would rise.

With nearby airports closed because of poor visibility, ventilators needed for burn victims were stuck in the capital, Jakarta, he said. In meantime, nursing students were using emergency respirators pumped by hand.

The volcano, in the heart of densely populated Java island, has erupted many times in the last two centuries, but many people choose to live on its rolling slopes, drawn to soil made fertile by molten lava and volcanic debris.

In recent days, however, more than 200,000 people have crammed into emergency shelters in the shadows of the volcano, which continued to rumble and groan Saturday. At times it spit gray clouds of ash and gas up to five-miles (eight-kilometers) -high.

"It's scary. ... The eruption just keeps going on," said Wajiman, 58, who was sitting in a shelter near a girl reading a newspaper headlined "Merapi isn't finished yet."

Crammed together on muddy floors, flies landing on the faces of sleeping refugees, many complained of poor sanitation, saying there were not enough toilets or clean drinking water.

The village hardest hit on Friday, Bronggang, was nine miles (15 kilometers) from the glowing crater, still within the perimeter of the government-delineated "safe zone."

The zone has since been expanded to a ring 12 miles (20 kilometers) from the peak, bringing it to the edge of the ancient royal capital of Yogyakarta, which has been put on its highest alert.

The biggest threat to the city of 400,000 is the Code River, which flows into Yogyakarta from the 9,700-foot (3,000-meter) mountain and could act as conduit for deadly volcanic mudflows that form in heavy rains.

Racing at speeds of 60 mph (100 kph), the molten lava, rocks and other debris, can destroy everything in their path.

Merapi's latest round of eruptions began Oct. 26, followed by more than a dozen other powerful blasts and thousands of tremors.

With each new eruption, scientists and officials have steadily pushed the villagers who live along Merapi's slopes farther from the crater.

Towering plumes of ash continued to dust windshields, rooftops and leaves on trees hundreds of miles (kilometers) away Saturday. The ash created near white-conditions in Yogyakarta, that forced motorists to switch on their headlights and shutdown its airport for a second day.

The fallout was so bad, that two international airlines, Malaysia Airlines and budget-carrier AirAsia, decided to cancel or reroute flights that were supposed to land in the city of Bandung, 220 miles (380 kilometers) west of Merapi.

The latest eruption released 1,765 million cubic feet (50 million cubic meters) of volcanic material, making it "the biggest in at least a century" at Merapi, state volcanologist Gede Swantika said as plumes of smoke continued to shoot up more than 30,000 feet (10,000 meters).

Priohutomo, the hospital official, said the mountain has killed 138 in the last two weeks.

More than 200 injured people -- with burns, respiratory problems, broken bones and cuts -- waited to be treated at three different hospitals.

"We're totally overwhelmed here!" hospital spokesman Heru Nogroho said.

Some of Merapi's victims had burns covering up to 95 percent of their bodies.

The facility's burn unit is limited to 10 beds, however, and it turns away any patient without facial burns or whose body is burned less than 40 percent, said Priohutomo.

Indonesia, a vast archipelago of 235 million people, is prone to earthquakes and volcanoes because it sits along the Pacific "Ring of Fire," a horseshoe-shaped string of faults that lines the Pacific Ocean.