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

Researchers predict the most likely outcome of the unrest at Mt. Spurr is “one or more explosive events” that could last as long as a few hours and produce ash clouds carried for hundreds of miles.

Increasing volcanic activity at the over 11,000-foot-tall, snowcapped volcano in Alaska is likely a sign of its impending first eruption since 1992, experts say. Mount Spurr, located about 75 miles West of Anchorage,