Scientists at the Alaska Volcano Observatory are using data gathered from daily aircraft flights over Mount Redoubt, along with information from other sensors, to try to determine whether and when the volcano is going to erupt.
The volcano, located about 100 miles southwest of Anchorage, is expected to erupt within days or weeks causing enormous clouds of ash which may pose a danger to aircraft.
"It's a very severe hazard because jet engines run at a very high temperature," says geologist Michelle Coombs. "And once that silica-rich ash gets ingested into the engine, it can remelt and coat the insides of the engines and freeze up those engines."
According to our pdf archive, the day after the 1989 eruption of Redoubt, a KLM Boeing 747 flew into an ash cloud near Anchorage and all four engines stalled. The pilot was able to relight two of the engines and brought the aircraft down safely at Anchorage.