Alaska volcano sends up ash cloud

An Alaska volcano that has been erupting periodically for more than seven months sent up another ash cloud, prompting a warning to transcontinental aircraft.

Bogoslof Volcano, in the Aleutian Islands about 1,400 kilometres southwest of Anchorage, erupted at 10 a.m. Monday and spewed ash for three hours until about 1 p.m.

Satellite data showed the eruption rising above clouds at 450 metres. A pilot later reported seeing the ash cloud at 9,750 metres.

Bogoslof Volcano is a cone-shape structure with its base 1,675 metres under water on the floor of the Bering Sea. The tip forms tiny Bogoslof Island, and previous eruptions have added or subtracted acreage.

The volcano has erupted about 60 times since mid-December, said Dave Schneider, a U.S. Geological Survey geophysicist with the observatory, usually in spurts far less than three hours. Previous eruptions have been from vents under the sea.

“We think this was still underwater today,” Schneider said.

Ash clouds above 6,100 metres can harm jet airliners travelling between Asia and North America on the Great Circle Route. Sharp volcanic ash can damage and even stop jet engines.

Pilots warned of ash clouds fly over or around them to avoid engine damage.

Satellite images in early afternoon showed a continuous ash cloud still attached to the volcano, according to the observatory.

Winds pushed the cloud south. Ash was not expected to present a danger to Alaska communities.

Low-level ash emissions may have continued. The observatory said seismic activity declined but remained above background levels and that emissions could intensify without warning.