Volcanic eruptions.

The 2010 eruptions of Eyjafjallajokull were volcanic events at Eyjafjallajokull in Iceland which, although relatively small for volcanic eruptions, caused enormous disruption to air travel across western and northern Europe over an initial period of six days in April 2010. Additional localised disruption continued into May 2010. The eruption was declared officially over in October 2010, when snow on the glacier did not melt. From 14–20 April, ash from the volcanic eruption covered large areas of Northern Europe. About 20 countries closed their airspace to commercial jet traffic and it affected approximately 10 million travellers.