Chile's Chaiten volcano erupts south of Santiago in this image captured by NASA's Terra satellite at 10:35 a.m. local time on May 3 and released on May 6, 2008. The image shows a long cloud-like plume of smoke and ash flowing southeast from the summit of the volcano across the Andes mountains, across part of Argentina and then dissipating over the Atlantic ocean.

Residents wearing surgical facemasks walk by in Argentina's Patagonian city of Esquel May 5, 2008. On Friday, in nearby Chile, the Chaiten volcano erupted, forming a mushroom cloud as ash shot high into the sky. It continued to belch hot gas and ash on Monday, sending sooty emissions as far as neighboring Argentina.