Chaitén Volcano, in Chile, has culminated three days of unexpected activity with a major eruption today that sent ash 30 kilometers high—that is, into the stratosphere. Before this week, its last documented eruption was about 7420 BCE. NASA's Earth Observatory has two satellite images of the volcano from yesterday. In the image a big ash plume crosses the continent, which admittedly is narrow at this latitude, about 45° south.

Not much is known yet scientifically. Another recent eruption in southern Chile, that of Cerro Hudson in 1991, released a large quantity of fluoride and sulfide gases into the stratosphere that subsequently contributed to a large Antarctic ozone hole. Chaitén is about 250 km north of Hudson and 150 km south of Puerto Montt, the end of the road.

Follow the official news from the Chilean geologic agency SERNAGEOMIN. If your Spanish isn't good, Google's translation service does a decent enough job. The agency is conducting daily overflights and is deploying a local seismic network.