Volcanic Plume Blankets S. America

A mammoth plume of ash and smoke from a newly erupted volcano in Chile is slowly working its way across South America and now poses a health risk to the 8 million residents of Beunos Aires, AFP reports. Thousands of residents of southern Chile were evacuated Tuesday, with ash coating city streets and health officials urging people to don masks.

"Everything depends on which way the wind blows," said one meteorologist in Argentina. The 19-mile-high plume of smoke has canceled flights throughout the region. Meanwhile, a volcano expert warned that the eruption is only in its early stages and warned that a "major explosion" could collapse the volcano's cone. (More volcano stories.)