SANTIAGO // An erupting Chilean volcano has sent a towering plume of ash across South America, forcing thousands from their homes, grounding airline flights in southern Argentina and coating ski resorts with a gritty layer of dust instead of snow.
Booming explosions echoed across the Andes as toxic gases belched up from a five-kilometre fissure in the Puyehue-Cordon Caulle volcanic complex, a ridge between two craters just west of the Chilean-Argentine border that began erupting on Saturday.
Winds blew a 10-kilometre-high cloud of ash all the way to the Atlantic Ocean by late Monday and even into southern Buenos Aires province, hundreds of kilometres to the north-east.
Yesterday, domestic and international flights from the two Buenos Aires airports, the busiest in Argentina, were suspended due to the ash. Authorities in Chile went house to house on Monday, trying to persuade stragglers near the volcano to leave because of an increasing danger of toxic gas and flash floods. About 4,000 people had been evacuated from more than 22 communities. They began fleeing as swarms of earthquakes on Saturday heralded the eruption and hundreds more fled on Monday to shelters farther away.
Some refused to leave, wanting to protect their homes and livestock. Chile's verdant lakes region is a centre for dairy farming, with more than 9,000 cows and sheep.
Deputy interior minister Rodrigo Ubilla said about 50 families in the Rininahue area refused to abandon their homes.
Just north of the complex of volcanoes, the city of Futrono and the communities of Lago Ranco and Entre Rios were particularly vulnerable to flash floods. Some people also refused to leave Mantilhue, along the Rio Bueno, or "Good River," just 10km from the eruption. While the evacuation order was not yet mandatory, a group of Mapuche Indians said they would seek the regional governor's authorisation to enter the area to pray for the volcano to stop erupting.
Enrique Valdivieso, the director of Chile's National Geology and Mines Service, said the fissure was belching toxic gases and material that could clog rivers and force them to overflow.
Spectacular displays of lightning flashed in the volcanic clouds during the weekend, and while the amount of ash falling east of the volcano subsided significantly by Monday, experts said it was too early to predict how long it will take before the volcano falls silent.
The Cordon Caulle is nearly 1,000km south of Santiago, in Chile's lakes region, just west of Bariloche. Authorities went on alert before the eruption on Saturday when as many as 240 tremors an hour struck the region.
The volcano's last major eruption was in 1960, shortly after a 9.5 magnitude earthquake, the most powerful in recorded history, struck Chile.
Some scientists have said that last year's 8.8 quake in Chile increased the likelihood of volcanic activity because of shifts in pressure along the Earth's tectonic plates.
* Associated Press with additional reporting by Agence France-Presse