Air traffic was sharply curtailed on the continent as the ash cloud drifted over Argentina, Uruguay and into Brazil. Flights in and out of the Argentine capital Buenos Aires, a key regional hub, were canceled for most of the day.

Rain mixed with volcanic ash poured down on communities near the Puyehue volcano, raising fears that the weight of falling water and volcanic materials could cause mudslides and threaten dams in the area, some 870 kilometers (540 miles) south of the capital Santiago.

A milky coating of ash settled on the waters of Gol Gol river, which was swollen by heavy rains.

"We are concerned about water that can drag the volcanic material certain places and cause some dams to fall," Public Works Minister Hernan de Soliminhac said.

Enrique Valdivieso, director of Chile's National Service of Geology and Mines (Sernageomin), said heavy rains would not quell the power of the volcano but could bring gases and ash to the surface, contaminating nearby rivers.   

AFP