SANTIAGO A towering ash cloud spewing from a volcano in south-central Chile could disrupt air traffic for some time as the eruption shows no signs of stabilizing in the near term, experts said on Tuesday.
Ash from a volcano in Chile's Puyehue-Cordon Caulle chain that erupted on June 4 after decades lying dormant has forced the sporadic cancellation of hundreds of flights, especially in neighbouring Argentina and Uruguay.
Flights as far away as Australia have been grounded because of the ash, which can damage jet engines, and the chaos in South America has buffeted airlines including Chile's LAN LAN.SN(LFL.N) and Brazil's TAM TAMM4.SA and Gol (GOLL4.SA)(GOL.N).
"There are no signs that the situation is going to change or stabilize in the short term", said Enrique Valdivieso, director of Chile's national service of geology and mining (Sernageomin).
"Fine ash, like we have seen from this latest eruption, could last (in the air) for months. If the ash column continues to measure up to 5.5 miles (9 km), it can spread easily. The higher the ash, the more it is blown elsewhere."
He said it was hard to predict how long the ash cloud would continue to affect flights. If the eruption intensifies, it could increase the amount of ash belched into the atmosphere.
Brazilian authorities said the volcanic ash had reached the southern cities of Porto Alegre and Florianopolis.
Airports in Buenos Aires were expected to start reopening late on Tuesday as the ash cloud dissipated and activity was gradually resuming at Uruguay's main international airport.
Air travel in northern Europe and Britain was hit last month after Iceland's most active volcano at Grimsvotn sent a thick plume of ash and smoke 15.5 miles (25 km) into the sky.
In April last year, the eruption of another Icelandic volcano, Eyjafjallajokull, led to 100,000 cancelled flights, affecting 10 million people at a cost of $1.7 billion.
Chilean volcanoes tend to spew more ash than European volcanoes like Iceland's, because the magma is thicker and rises more slowly. As a result more ash is expelled.
"If we take the case of Chile's Lonquimay volcano in 1989, the plume lingered for about two months," said Felipe Aguilera, a volcanologist at Universidad de Atacama.
It was the latest in a series of volcanic eruptions in Chile in recent years. Chile's Chaiten volcano erupted spectacularly in 2008 for the first time in thousands of years, spewing molten rock and a vast cloud of ash that reached the stratosphere.
The Llaima volcano, one of South America's most active, erupted in 2008 and 2009.
Chile's chain of about 2,000 volcanoes is the world's second-largest after Indonesia. Some 50 to 60 are on record as having erupted, and 500 are potentially active. (With additional reporting by Maximiliano Rizzi, Luis Andres Henao, Guido Nejamkis and Malena Castaldi; Editing by Eric Walsh)