ANCHORAGE, Alaska — Alaska's Mount Redoubt volcano erupted four times overnight, sending an ash plume more than 9 miles into the air in the volcano's first emission in nearly 20 years.Residents in the state's largest city was spared from falling ash, though fine gray dust was falling Monday morning on small communities north of Anchorage.Ash from Alaska's volcanos is like a rock fragment with jagged edges and has been used as an industrial abrasive. It can injure skin, eyes and breathing passages. The young, the elderly and people with respiratory problems are especially susceptible to ash-related health problems.The ash can also causes problems in planes.Alaska Airlines on Monday canceled 19 flights in and out of the Anchorage international airport because of the ash.Elmendorf Air Force Base in Anchorage told only essential personnel to report to work. The Air Force says 60 planes, including fighter jets, cargo aircraft and a 747 commercial plane, were being sheltered.The first eruption, in a sparsely area across Cook Inlet from the Kenai Peninsula, occurred at 10:38 p.m. Sunday and the fourth happened at 1:39 a.m. Monday, according to the Alaska Volcano Observatory.The wind patterns were taking the ash cloud away from Anchorage, toward Willow and Talkneetna, near Mount McKinley, North America's largest mountain in Denali National Park.Dave Stricklan, a hydrometeorogical technician with the National Weather Service, expected very fine ash."Just kind of a light dusting," he said. He said the significant amount of ash probably dropped immediately, right down the side of the volcano."The heavier stuff drops out very quickly, and then the other stuff filters out. There's going to be a very fine amount of it that's going to be suspended in the atmosphere for quite some time," he said. "The finer ash is going to travel farther, and any ash can affect aviation safety."The 10,200-foot Redoubt Volcano, roughly 100 miles southwest of Anchorage, last erupted during a four-month period from 1989-90.In its last eruption, Redoubt sent ash 150 miles away into the path of a KLM jet and its four engines flamed out. The jet dropped more than 2 miles before the crew was able to restart all engines and land safely. The plane required $80 million in repairs.Meanwhile, the volcano became restless earlier this year. The observatory had warned in late January that an eruption could occur at any time.Increased earthquake activity over the past 48 hours prompted scientists to raise the alert level for Mount Redoubt on Sunday.On Sunday morning, 40 to 50 earthquakes were being recorded every hour.A steam plume rising about 1,000 feet above the mountain peak was observed Saturday.___a 5TH ERUPTION has occured
