Scientist taking samples and measuring the ash fall from Grimsvotn volcanic eruption, Iceland - stock photo

Team on ash covered glacier approx. 35 kilometers from the crater. The eruption began on May 21, 2011 spewing tons of ash; initially the plume was over 20 kilometers high. Volcanic ash is an extreme danger to jet engines closing airspace in Iceland and parts of Europe. Grimsvotn is Iceland's most frequently erupting basalt volcano located under Vatnajokull Ice Cap; the largest glacier in Europe. The prior eruption was in 2004. Date photographed May 30, 2011