More from Eyjafjallajokull (3)

This aerial image shows the crater spewing ash and plumes of grit at the summit of the volcano in southern Iceland's Eyjafjallajokull glacier Saturday April 17, 2010. (AP Photo/Arnar Thorisson/Helicopter.is)
A pilot takes pictures of the Eyjafjallajokull volcano billowing smoke and ash during an eruption on April 17, 2010. (HALLDOR KOLBEINS/AFP/Getty Images)

Construction crews repair a road damaged by floods from glacial melting caused by a volcano in Eyjafjallajokull, Iceland April 17, 2010. (REUTERS/Lucas Jackson)

Horses graze in a field near the Eyjafjallajokull volcano as it continues to billow dark smoke and ash during an eruption late on April 17, 2010. (HALLDOR KOLBEINS/AFP/Getty Images)

Ingi Sveinbjoernsso leads his horses on a road covered volcanic ash back to his barn in Yzta-baeli, Iceland on April 18, 2010. They come galloping out of the volcanic storm, hooves muffled in the ash, manes flying. 24 hours earlier he had lost the shaggy Icelandic horses in an ash cloud that turned day into night, blanketing the landscape in sticky gray mud. (HALLDOR KOLBEINS/AFP/Getty Images)

The ash plume of southwestern Iceland's Eyjafjallajokull volcano streams southwards over the Northern Atlantic Ocean in a satellite photograph made April 17, 2010. The erupting volcano in Iceland sent new tremors on April 19, but the ash plume which has caused air traffic chaos across Europe has dropped to a height of about 2 km (1.2 mi), the Meteorological Office said. (REUTERS/NERC Satellite Receiving Station, Dundee University, Scotland)

A woman makes a phone call in the empty arrival hall of Prague's Ruzyne Airport after all flights were grounded due to volcanic ash in the skies coming from Iceland April 18, 2010. Air travel across much of Europe was paralyzed for a fourth day on Sunday by a huge cloud of volcanic ash, but Dutch and German test flights carried out without apparent damage seemed to offer hope of respite. (REUTERS/David W Cerny)

Lava and lightning light the crater of Eyjafjallajokul volcano on April 17, 2010. (REUTERS/Lucas Jackson)

The first of 3 photos by Olivier Vandeginste, taken 10 km east of Hvolsvollur at a distance 25 km from the Eyjafjallajokull craters on April 18th, 2010. Lightning and motion-blurred ash appear in this 15-second exposure. (© Olivier Vandeginste)

The second of 3 photos by Olivier Vandeginste, taken 25 km from the Eyjafjallajokull craters on April 18th, 2010. The ash plume is lit from within by multiple flashes of lightning in this 168 second exposure. (© Olivier Vandeginste)

The third of 3 photos by Olivier Vandeginste, taken 10 km east of Hvolsvollur Iceland on April 18th, 2010. Lightning flashes and glowing lava illuminate parts of Eyjafjallajokull's massive ash plume in this 30-second exposure. (© Olivier Vandeginste)