FAIRBANKS, AK — (CNN) A volcanic eruption in Alaska sent ash 20,000 feet up in the air and prompted flight warnings, according to authorities.

The Pavlof Volcano, located on the Aleutian Islands, began “erupting abruptly” Sunday afternoon, according to the Alaska Volcano Observatory.

A volcano alert warning remained in effect early Monday morning, and the aviation warning color code remains red, its highest level.

Ash was reportedly moving north after the eruption, according to the volcano observatory.

Seismic activity was also reported after the quake.

The volcano last erupted in November 2014.

A few planes appeared to be flying nearby early Monday morning Eastern Time, according to Flightaware.com.

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