An Alaska volcano erupted Tuesday night and spewed ash for more than an hour. The Alaska Volcano Observatory says Bogoslof (BOH-gohs-lawf) Volcano erupted at 10:32 p.m. and continued for 73 minutes. A pilot reported the eruption produced an ash cloud that reached 34,000 and the observatory issued a warning to pilots. Wind pushed the cloud southwest. Ash from southwest Alaska volcanos is a threat to airliners operating between North America and Asia when a cloud rises above 20,000 feet. Ash can harm and stop jet engines. Bogoslof has been erupting periodically since mid-December. The observatory says additional explosions producing high-altitude ash could occur at any time. The volcano is 850 miles southwest of Anchorage in the Aleutian Islands.