NEW : National Weather Service issues an advisory for areas around the coast . An expert reports ash plumes 20,000 feet above sea level over the Pavlof Volcano . That and another Alaska volcano are on second highest alert ##s . Power described Pavlof as `` one of the most historically active volcanoes in the Northern Hemisphere . '' An expert notes volcanic eruptions over Alaska can seriously affect air travel .
NEW : National Weather Service issues an advisory for areas around the coast . An expert reports ash plumes 20,000 feet above sea level over the Pavlof Volcano . That and another Alaska volcano are on second highest alert ##s . An expert notes volcanic eruptions over Alaska can seriously affect air travel .