Because winds are moving in different directions at different elevations around the Augustine Volcano, an ash fall advisory was issued for communities along the southwest portion of the Kenai Peninsula and east of the volcano, in the Kamishak and Iliamna bays.
"Light ash can be expected, nothing that would accumulate in any thickness," said Michelle Coombs, a geologist at the observatory.
The eruption lasted for five minutes, and started just before 8 a.m.
Six eruptions were recorded on Friday and early Saturday from the 4,134-foot volcano before it was downgraded Sunday after a 30-hour period without eruptions.
Tuesday's eruption was likely similar in style to the six significant eruptions last week, "but a little more energetic," Coombs said.
Most of last week's eruptions reached 30,000 feet, or about 5½ miles. However, a pilot reported one plume at the 10-mile level.
Tuesday's eruption was preceded by increased seismic activity at the volcano, located on an uninhabited island about 180 miles southwest of Anchorage. That prompted observatory officials to raise the volcano's threat level to red, meaning an eruption was imminent.
Last week's blasts sent plumes of ash drifting northeast across Cook Inlet into several Kenai Peninsula communities, where a fine layer of ash fell.
The most recent explosion occurred just after midnight on Saturday. It was followed by a lull lasting into Sunday afternoon, when officials had lowered the earlier red warning level to orange.
The 4,134-foot Augustine Volcano began erupting Wednesday after a 20-year lull.
The ash clouds can pose a health risk, especially for people with respiratory problems, and they can damage the engines of aircraft and vehicles on the ground.
Alaska Airlines, which canceled 28 flight into Anchorage and Fairbanks on Friday and early Saturday as a safety precaution, resumed its schedule Saturday morning, but officials said they would still keep a cautionary eye on the wind and volcano.
Charlie Franz, chief executive officer of South Peninsula Hospital in Homer, said last week his staff was putting extra filters in the hospital's air handling system.
"Just don't go out if you don't have to," he said. "I think that's probably the best advice people can get.