STEAMING RIVERS FILLED with hot ash, rocks, and rain threatened to overflow their banks in southern Chile on Friday and ash clouds from a volcano that began erupting nearly a week ago kept major airports closed across much of the southern part of the continent.

In towns bordering the Cordon Caulle volcano, authorities warned that rivers were about to flood due to the large amounts of ash and volcanic rock that have fallen in them and heavy rains that have doused the area of southern Chile.

About 3,500 residents had been evacuated, and 500 of them were still in shelters Friday. Authorities were seeking legal permission Friday to evacuate a dozen more who refused to leave their property and animals behind.

The flow of the Nilahue and GolGol rivers near the volcano had increased from 30 cubic metres per second to 160 cubic metres per second, Chilean Public Works Minister Hernan de Solminihac said on state television Friday.

“It’s important that people leave their homes for their own security, because the volcano has not ceased to erupt,” he said.

Tons of hot volcanic material had raised the temperature of the River Nilahue to 45 degrees Celsius, killing off large numbers of salmon, Solminihac said. The average air temperature this time of year in the region is about 10 degrees Celsius.

Residents of the Argentine capital, Buenos Aires, and the neighboring Uruguayan capital of Montevideo, awakened Friday to ash-covered streets, sidewalks and automobiles.

And those who tried to leave, found airports remained closed because of the clouds of fine grit that can damage airplane engines.

An emergency committee from several Argentine government agencies announced Friday that air traffic should be resumed in Buenos Aires by Friday evening if the cloud moves away as expected.

Airports in Brazil and Chile also canceled numerous flights as a precaution.

The volcano, which began erupting last Saturday, has also affected a dozen nearby Chilean farming towns, as well as winter resorts in southern Argentina’s Patagonia region, including San Carlos Bariloche, Villa La Angostura, San Martin de los Andes and Esquel.

The Southern Hemisphere’s winter begins on June 21, and resort operators are concerned that a prolonged eruption could keep away tourists.

In San Carlos de Bariloche, more than 65 percent of the nearly 4.5 billion pesos collected by businesses in the town last year came in the three winter months, according to government statistics. About 250,000 tourists arrive each year in the city, which is more than 1,000 miles southwest of Buenos Aires.

Workers in the resort city filled 600 dump trucks Thursday with the ash that had fallen on the airport’s main runway. Officials have said that the airport would be closed at least until June 21.

- AP