After a brief respite, an Iceland volcano has erupted for a second time, but from a different, glacier-covered vent. Melting ice spurred an emergency nighttime evacuation of hundreds of people in the flood zone.
About 800 people living nearby were evacuated as a precautionary measure at the first signs of the second eruption, said Páll Einarsson, a geophysicist at the University of Iceland's Institute of Earth Sciences. There are no reports of casualties so far.
But initial reports suggest glacial melt from Iceland's Eyjafjallajökull volcano, located about 75 miles (120 kilometers) from Reykjavik, has raised local rivers by as much as ten feet (three meters).
A major road has been closed and, as of press time, water continues to gush into the ocean.
Iceland Volcano Still Active
Eyjafjallajökull first erupted on March 20, 2010, in a fiery display that sent fountains of lava shooting high into the air and ribbons of lava flowing down cliff faces. (See pictures of the initial Iceland volcano eruption.)
That eruption, the volcano's first in nearly 200 years, opened up new vents nearby and built a 27-story-tall cone of magmatic rock.
After an initial evacuation of nearby villages in March, flooding fears subsided and the Iceland volcano quickly became a popular tourist attraction. (Iceland Volcano Pictures: Eruption Sparks Tourist Boom.)
As of April 13, Eyjafjallajökull's eruption seemed to be quieting down. But just hours later another eruption broke out on another part of the volcano.
"It's still going on, and probably still increasing at the moment," Einarsson said.
Steep Volcano = Fast Floodwaters
The initial series of eruptions did not trigger flooding, because the active vents were in a mostly ice-free part of the landscape, Einarsson explained. (See aerial pictures of the Iceland volcano.)
By contrast, the current eruption started beneath a 650-foot-thick (200-meter-thick) block of ice. Heat from the eruption quickly transformed the glacier into a fast-flowing torrent of water.
"The volcano is quite steep, so the floodwater comes down rather powerfully in a short time," Einarsson said. "We were nervous that we would not be able to evacuate people in time, but this was quite successful."
Another danger associated with Eyjafjallajökull's eruption is that it could agitate a neighboring volcano, called Katla, which sits about 12 miles (20 kilometers) away.
"Historically," Einarsson said, "the eruption of [Eyjafjallajökull] has triggered the eruption of Katla."