The 2010 eruptions of Eyjafjallajökull are a sequence of volcanic events at Eyjafjöll in Iceland which, although they were not huge in volcanic terms, caused enormous disruption to air travel across western and northern Europe over an initial period of 6 days in April 2010. Additional localised disruption continues into May 2010.
Seismic activity started at the end of 2009 and gradually increased in intensity until on 20 March 2010, a small eruption started that was rated as a 1 on the Volcanic Explosivity Index.
Beginning on 14 April 2010, the eruption entered a second phase and created an ash cloud that led to the closure of most of Europe's IFR airspace from 15 April until 20 April 2010. Consequently, a very high proportion of flights within, to, and from Europe were cancelled, creating the highest level of air travel disruption since the Second World War.
The second phase of the eruption started on 14 April 2010 and resulted in an estimated 140 million cubic metres (180,000,000 cu yd) of ejected tephra. The ash plume rose to a height of approximately 9 kilometres (30,000 ft), which rates the explosive power of the eruption as a 4 on the Volcanic Explosivity Index.