A massive ash plume from the volcano in Iceland has caused major air-traffic disruption in the UK and north-west Europe since 14 Apr:
news.bbc.co.uk/2/hi/uk_news/8625813.stm
Something interesting is that the EUMetsat geostationary satellite images have a channel that shows ash/aerosol clouds:
oiswww.eumetsat.org/IPPS/html/MSG/RGB/ASH/
Several of the images posted on the BBC article (above) are from this source.
A major plume can be seen starting in Iceland from about 21Z on 14th Apr:
oiswww.eumetsat.org/IPPS/html/MSG/RGB/ASH/ICELAND/
