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,