Indonesia's rumbling Mount Merapi unleashed a column of hot gas and sent clouds of ash tumbling down its slopes Thursday as 15,000 terrified villagers fled to safety. Some jumped in rivers to escape the searing heat, while others dashed down the volcano or clambered onto the backs of trucks.
"I thought, this is it," said Udi Sutrisno, who grabbed a bag of clothes and fled his beloved farm with his wife and 10-year-old son, sirens wailing in the background. "We ran as fast as we could."
Indonesia's most dangerous volcano has been venting steam and ash for weeks, but Thursday's 9 a.m. burst was the largest yet, sending billowing, dark gray clouds avalanching 3 1/2 miles down the mountain, said Sugiono, a government vulcanologist.
It was one of a series of powerful explosions, some spewing columns of ash 1 mile high.
Some scientists say a May 27 earthquake that killed more than 5,700 people in an area 25 miles south of Merapi may have contributed to the volcano's volatility in recent weeks.
The mountain's lava dome has swelled, raising concerns that it could suddenly collapse, sending scalding clouds of fast-moving gas, lava and rocks into still-populated areas.
Yousana Siagian, a senior official at the government's Vulcanology and Disaster Mitigation Center, said a shallow 4.2-magnitude aftershock Thursday, 17 miles south of the peak, may have speeded things along.
Farmers carrying heaps of grass on their head ran down the mountain beneath a rain of ash, as others zipped off on motorcycles. Women clutched children as they jumped into trucks and cars, wiping away tears when they reached emergency shelters.
"I only had time to gather clothes for my children," said Sartini, 24, one of hundreds of people seeking refuge at a makeshift camp set up in a field dotted with Red Cross tents.
As she spoke, a red truck carrying 30 men, women and children lumbered into the camp in front of a government office, many smiling with relief.
Sutomo, a government official at the scene, said 3,500 people had fled Sleman district on Merapi's southern side. Another 12,000 left their villages in Magelang district on the west.
Authorities had earlier urged residents to evacuate the danger zone near the volcano's peak, but thousands stayed behind saying they wanted to tend to livestock and crops on the fertile slopes.
"Of course, we're worried," Supriatun said by mobile phone, adding that her small dairy farming community was so far untouched. "But as long as the hot clouds do not reach us, we won't go."
Merapi's last deadly eruption was in 1994, when it sent out a searing gas cloud that burned 60 people to death. About 1,300 people were killed when it erupted in 1930.
Authorities said that another major, deadly eruption would severely strain ongoing earthquake relief operations in nearby Bantul and Klaten districts. More than a half-million people were displaced in last month's temblor, many living in makeshift shelters with no toilets or running water.
"If there's a large blast at Merapi that causes deaths and injuries, we'll need help from paramedics now deployed in the quake zone — especially with severe burns," said Imam Purwadi, a government official overseeing relief efforts at both sites.
Indonesia is located along the so-called "Ring of Fire," an arc of volcanoes and fault lines encircling the Pacific Basin.
Volcanos in the central Philippines and southern Japan have also spewed ash and hot steam in recent days, but there were no reports of damage or injuries.