It was the first time that any of the mountain’s latest eruptions have brought such a large quantity of ash to south-central Alaska.

Redoubt is located about 100 miles southwest of Anchorage, and began erupting on March 22. Its ash cast an eerie blue tint to the air above Alaska’s largest city, and brought a sulfurous smell to the air that caused raspy throats and burning eyes.

Federal and state officials established a unified command to respond to the volcano's impact on a nearby oil storage facility that holds more than 6 million gallons of oil. Experts were exploring way to remove most of the oil from the facility's storage tanks.

Redoubt’s last eruptive phase was in 1989-90. A 1989 blast sent ash into the path of a KLM flight carrying 231 passengers, flaming out its four engines. Pilots ultimately restarted the engines and landed safely.

Photo: Chris Waythomas - Alaska Volcano Observatory