Alaska's Mount Redoubt volcano erupted with four large explosions last night that shot a huge plume of gas and smoke 15 kilometres into the air and sent ash drifting toward the state's largest city Anchorage.
"It is in full eruption," said Matthew Haney, a research geophysicist with the Alaska Volcano Observatory.
Mount Redoubt, which is some 170 kilometres from Anchorage, rises 3,108 metres above the Kenai Peninsula. About 50,000 people live on the peninsula within 80 kilometres of the mountain and it is one of the most densely populated areas of the state.
The National Weather Service issued an ash-fall advisory and some flights into Anchorage airport have been canceled.
Authorities are preparing for mudslides and floods from hot lava melting snow and ice on the glacier, said John Power, an observatory geophysicist.
Authorities raised the alert level for Mount Redoubt on March 15th to orange from yellow after low-level tremors that began in January gained intensity. The alert rose to red, the highest level of four, yesterday.
The volcano had a series of eruptions in 1989 and 1990 that disrupted air traffic, the local oil industry and schools.