Several flights to the capitals of Chile, Argentina, and Uruguay have been canceled as ash from the Chilean volcano Calbuco, which erupted earlier this week, reached as far as southern Brazil on Saturday.

Calbuco erupted twice in 24 hours on Wednesday and Thursday, sending up an 11-mile high cloud and coating nearby towns in a thick layer of ash.

As reported in Reuters, Chilean authorities have set up a 12-mile cordon around Calbuco, in the scenic Los Lagos region, which is about 620 miles south of the capital of Santiago. More than 6,500 people in the area were evacuated.

Chile's national office of emergency stated in its latest report, "The dangerous nature of volcanic activity like this, plus the volcano's current instability that could lead to more intense activity in the short term, indicates we should maintain the perimeter."

Authorities briefly let people who had been evacuated from the scene return to their homes on Saturday in order to check on their houses and animals and to pick up any clothes and medication that they might need.

Due to the weight of the volcanic ash, some houses and schools located close to the Calbuco have already collapsed.

The dangerous ash presents a real threat to air traffic, as particles in the atmosphere can cause problems for planes. Argentine air traffic has been the most affected by the ash so far.

As a precautionary measure, Delta Air Lines, Air France, American Airlines, Air Canada, and Qantas Airways have suspended flights from and to the airports of Santiago, Buenos Aires, and Montevideo.

Chile's LAN and Aerolineas Argentinas, however, were operating flights as usual from those airports. A spokesman for Argentina's National Civil Aeronautic Administration, stated, "The situation is much better than yesterday."