Kilauea Spews Boulders in 5-Mile-High Eruption
Webcams that operate 24/7 faithfully recorded the ashy cloud that reached as high as some commercial airplanes fly.
Credit: U.S Geological Survey

An explosion at Kilauea volcano's summit spawned chunky boulders and a tremendous volcanic cloud that reached as high as commercial airplanes fly — about 30,000 feet (5.6 miles, or 9.1 kilometers) above sea level — early this morning (May 17) local time.

The explosion began as the volcano spewed out boulders hundreds of feet into the air at 4:15 a.m. Hawaii Standard Time, according to the U.S. Geological Survey (USGS). The earth-shattering event happened at the Overlook Vent, which holds a lava lake known as Halema'uma'u. On May 10, geologists with the Hawaiian Volcano Observatory (HVO) said that as Halema'uma'u drained further, there was a risk it could intersect with the water table underground, and heat that groundwater. If the crater's conduit became plugged by infalling boulders, the trapped steam could erupt dramatically, spewing boulders.

The new explosion sent Kilauea into code red, the highest-level warning for the volcano on Hawaii's Big Island, according to the HVO. [Photos: Fiery Lava from Kilauea Volcano Erupts on Hawaii's Big Island]

The miles-high ashy plume is drifting northeast, and it isn't a loner. The summit continues to emit plumes, some as high as 12,000 feet (2.2 miles, or 3.6 km) above sea level, the HVO said, adding that "at any time, activity may again become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent."

An animated GIF the USGS tweeted out shows how far the ash cloud might travel.

The National Weather Service has issued an ashfall advisory until 12 p.m. HST, the Hawaii County Civil Defense reported. Due to elevated sulfur dioxide levels in the area, local schools are also closed, the Hawaii County Civil Defense said.

The explosion is part of the heightened geologic activity around Kilauea that began in mid-March. You can find more of Live Science's coverage here.

Original article on Live Science.