Yes, I thought volcano, too. I lived in Portland when Mt. Saint Helen's blew so I remember what it looks like from that time. I don't have a TV so haven't seen any images of the Icelandic eruption. Glassy-skied is right...all that silica floating around. It killed my '67 Volkswagen. You would find it in everything for months and months afterward. Nasty stuff but interesting to look at.
or maybe 'TheShadow' from Inkheart. though it was blacker.. silica not too good for jet engines either... i imagine wool has silica content.....thnx l,d,t,s i'll have to do a proper referenced one now :)
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http://www.public.asu.edu/~cftaylo1/images/spinning_wheel/raw.jpg