This is the top vent at the summit of Mount Redoubt in Alaska on March 21. Two days later and the volcano had erupted five times, sending an ash plume more than 9 miles into the air for the first time in nearly 20 years.
The ash from Alaskan volcanoes is like a rock fragment with jagged edges and has been used as an industrial abrasive. It can injure skin, eyes and breathing passages. Airlines have cancelled flights and the Air Force Base in Anchorage has moved planes into shelters to stop any damage.
The 10,200-foot volcano is roughly 100 miles southwest of Anchorage and in the last eruption sent ash 150 miles away into the path of a KLM jet causing its four engines to flame 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.
The glacier on the slopes flows into the Drift river and the raised temperatures have increased the melt water run-off. The heavier ash falls fairly quickly but the fine ash is suspended for longer and is easily blown for miles by any atmospheric wind.