Current trajectory model (click on image for fullsize)
The graphic below depicts a model simulation of prospective ash trajectory IF Redoubt Volcano was to erupt. It does not mean the volcano has erupted. These trajectories are automatically run every 6 hours independent of the state of the volcano.
See here for a tutorial on interpreting trajectories.
Mount Redoubt releasing clouds of ash on March 15, 2009. Mount Redoubt, an active volcano west of Anchorage, Alaska, has erupted, according to the USGS Volcano Center.

Between 10:38pm on March 22 and 1:39am Alaska time on March 23, the USGS recorded four explosions at the volcano, which had been giving indications of an imminent eruption since 15 March. The USGS has issued a "code red" aviation warning and a volcano warning.

According to the Alaska Volcano Observatory, a fifth explosion began at about 4:38am Alaska time.

According to the National Weather Service, showers of volcanic ash have already been reported in Skwentna, Alaska and are possible in the Susitna Valley. Residents of those areas are advised to minimize driving, cover air intakes and open water supplies, and remain indoors.

However, Peter Cervelli of the Alaska Volcano Observatory said that "Anchorage might dodge the bullet" and come through the eruption unscathed. Dave Stricklan of the National Weather Service predicted a "light dusting" of fine ash that would disrupt air travel but not seriously affect people on the ground. Mudflows may affect the Drift and Crescent Rivers.

Mount Redoubt last erupted in late 1989, causing mudflows which put an oil refinery at risk while ash from the eruption stalled the engine of a passing airliner. US$160 million worth of damage was estimated to have been caused.