A surge of searing gas raced down the sides of Mount Merapi on Friday, smothering houses, cattle and villagers in its path. The death toll after the volcano's largest eruption in a century soared to 122.

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 fertile slopes farther from the crater. But after initially predicting earlier eruptions would ease pressure under the magma dome, experts who have spent a lifetime studying the volcano now say the don't know what to expect.

Scientists can study the patterns of volcanoes, but their eruptions are essentially unpredictable, as Merapi's increasingly intense blasts have proved.

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