Mount Redoubt is acting up with greater intensity.
It's rumbling and grumbling and producing a substantial ash and steam plume.
On Sunday, scientists said there was a marked increase of seismicity at the volcano about 100 miles southwest of Anchorage.
One plume went to 18,000 feet.
The volcano has been in what is called a dome-building phase as it grows a lava dome in its crater.
The dome has grown considerably in recent weeks. A tongue of lava now has advanced about 550 yards down the Drift Glacier Gorge.
The volcano had its last major explosion on April 4.