Regarding the Eyjafjallajökull irruption :)

The 2010 eruptions of Eyjafjallajökull were volcanic events at Eyjafjöll 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 covered large areas of northern Europe when the volcano erupted. About 20 countries closed their airspace (a condition known as ATC Zero) and it affected hundreds of thousands of travellers.
Seismic activity started at the end of 2009 and gradually increased in intensity until on 20 March 2010, a small eruption started 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. 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 250 million cubic metres of ejected tephra. The ash plume rose to a height of approximately 9 kilometres, which rates the explosive power of the eruption as a 4 on the Volcanic Explosivity Index.
By 21 May 2010, the second eruption phase had subsided to the point that no further lava or ash was being produced. More seismic activity was produced.
By the morning of 24 May 2010, the view from the web camera installed on Þórólfsfell showed only a plume of water vapour surrounded by a blueish haze caused by the emission of sulphurous gases.
Due to the large quantities of dry volcanic ash lying on the ground, surface winds frequently lifted up an "ash mist" that significantly reduced visibility and made web camera observation of the volcano impossible.

Due to this massive volcanic eruption. about 500 farmers and their families had to be evacuated. The river water temperature also increased about  6°C, which was thought that this rise in water temperature is related to the eruption nearby and is affecting part of the drainage basin. The thick layer of ash that has fallen on some Icelandic farms and pastures at Raufarfell has become wet and compact, making it very difficult to continue farming, harvesting or grazing livestock.