Mount Spurr is one of 53 volcanoes in Alaska that have been active within the last 250 years. It is roughly 80 miles northwest of Anchorage.

In the shadow of Alaska's bustling city, Mount Spurr whispers of its ancient power. Elevated gas emissions suggest a restless giant beneath the surface.

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