Okmok Gets Busy

Okmok is a beautiful caldera on Umnak, in the Aleutian Islands, that has begun to erupt after taking a break for 11 years. The Alaska Volcano Observatory is following Okmok's activity closely, as it does all Alaskan volcanoes. So many trans-Pacific airline routes cross the Aleutians that it's imperative to help planes avoid ash clouds, which can knock out a jet engine when they're bad enough.
_{Okmok photo by Cyrus Read, image courtesy AVO/USGS}