“It is also possible that an eruption could occur with little or no additional warning,” the Alaska Volcano Observatory stated. “This would be extremely hazardous for recreators on Mount Spurr or near its drainages as well as those overflying the volcano.”

The Alaska Volcano Observatory said signs indicated a Mount Spurr eruption was likely, though not certain, in the weeks or months ahead.

A volcano near Alaska’s largest city is showing new signs of unrest, with experts saying the likelihood of an eruption at Mount Spurr has increased.