A cloud of smoke and ash billows from Iceland's Grímsvötn volcano on Saturday. The country's most active volcano, Grímsvötn sits beneath the Vatnajökull ice cap in the southeastern part of the island. The current eruption is the first for this peak since 2004, according to the New York Times.
Grímsvötn's 12-mile-high (19-kilometer-high) ash cloud prompted the country's four international airports to cancel flights on Sunday. Winds are pushing the ash westward toward the United Kingdom, where airline officials are preparing for possible impacts to London's Heathrow Airport by the end of the week, the Guardian newspaper reported. (Read more about why ash is so dangerous to airplanes.)
Even so, Grímsvötn is not expected to hinder air traffic across Europe with the same severity as Eyjafjallajökull's 2010 eruption, the Times reported. For example, the weight of Grímsvötn's ash particles will make them drop to the ground faster, according to the newspaper.
Photograph from AFP/Getty Images
Fleeing the Ash
Tourists leave the Islandia Hotel in Nupur, Iceland, where ash from the erupting Grímsvötn volcano choked the air on May 22. Some of the ash has settled over the capital city of Reykjavik, about 250 miles (400 kilometers) west of the volcano, according to the AFP news service.
Photograph by Vilhelm Gunnarsson, AFP/Getty Images
Flash Amid the Ash
Seen from the Vatnajökull ice cap, lightning streaks through an ash cloud billowing from the erupting Grímsvötn volcano on May 22.
So-called volcanic lightning is born of the same ingredients as lightning in a regular thunderstorm, Martin Uman, a lightning expert at the University of Florida in Gainesville, told National Geographic News in 2010. Those ingredients include water droplets, ice, and possibly hail all interacting with each other and with airborne particles—in this case ash from the eruptions—to cause electrical charging, Uman said.