Alaska's Mount Redoubt volcano is rumbling again.
The Alaska Volcano Observatory says a series of small earthquakes began occurring around the summit of the volcano Sunday and continued Monday. As a result, scientists have upgraded the volcano's alert status.
Redoubt, about 105 miles southwest of Anchorage, went through an eruptive period that led to major explosions earlier this year, including one that dusted Anchorage with ashfall.
The erupting volcano forced the Cook Inlet Pipeline Co. to remove millions of gallons of oil stored at the Drift River Terminal 22 miles away. Hundreds of airline flights also had to be canceled because of ash clouds this spring.
The last time Mount Redoubt had a similar period of activity was in late 1989 to spring 1990.