Mt. Redoubt in March 2009, prior to erupting
At ~10:30 PM (Alaskan Time) last night, Mt. Redoubt erupted. AVO and the Anchorage VAAC issued a Red Alert for ash as high as 50,000 feet (15,000 meters) around the volcano. Information is scarce about the exact nature of the ash cloud because of the fact that the volcano erupted at night. The eruption has contained at least 5 large explosion and at least one of the seismometers at the volcano has stopped reported (RSO). An ashfall advisory has been issued by the Weather Service, with ash predicted to fall throughout the Susitna Valley (which includes the town of Willow and Cantwell). AVO has warned Alaska residents near the volcano to make proper as precautions such as covering water sources and not going outside as the ash advisory is in effect. AVO has said that the volcano has erupted at least 5 times since the initial eruption at 10:30 PM last night.
Now, I have to admit, I just woke up out here on the West Coast so I'm trying to digest all this information before much coffee, but after first showing initial signs of eruption as early as last fall, and then ratcheting up the rumbling in January, Redoubt finally erupted for the first time in almost 20 years. AVO expects that the explosive eruption might continues for the next few weeks to months, if that patterns similar to the 1989-1990 eruptive events are followed. This will likely disrupt air travel - both freight and passenger - out of Anchorage (and flights have already been cancelled), along with affecting oil in the Cook Inlet as there is a very good likelihood and mudflows/lahars will wash down the Drift River Valley, potentially damaging the oil terminal in the outflow fan of the river.
I will update this information throughout the day as we get more details - like maybe images if the weather/daylight cooperate (keep an eye on the webcam), but sounds like the initial eruption was large if the 50,000 feet (15,000 meters) ash column estimates are accurate and that we can expect Redoubt to be noisy for weeks to come. If you have information or questions, please post them here. I'll try to get to them as soon as I can.