This is Mt. Redoubt, located just across Cook Inlet from Anchorage. The last time it erupted was during a 4 month eruptive period from Dec. 89 to April 90, during which it erupted several times. In the last week or so, it has suddenly gotten active again, and there is a likelihood that it will erupt sometime soon.
Depending on which way the wind is blowing when it happens to erupt, the ashfall may happen over Anchorage and Wasilla. So all the stores are selling out of dust masks and vehicle air filters, just in case. We cover our computers with plastic bags when we leave for the night, as volcanic ash is extremely abrasive and damaging to electronics, and gets into everything.
Updates on the volcano are available here: http://www.avo.alaska.edu/activity/Redoubt.php