volcanic

A volcanic eruption in Alaska sent ash 20,000 feet up in the air and prompted flight warnings, according to authorities.A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. 

(CNN)Alaska's Pavlof Volcano, which erupted unexpectedly over the weekend, continued to rumble and fling ash into the sky Monday, the Alaska Volcano Observatory said. The ash plume is now 37,000 feet high and trails some 400 miles to the northeast over the Alaskan interior. Aviation alerts were up in the region.