The years 1953 and 1992 are the closest references to eruptions of an active volcano that now worries the entire United States, as it is in a phase of growing activity and imminent

“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.