Did a reverse GIS and found this:
https://www.google.com/search?q=eruption+of+the+cordon+caulle+chile&sa=X&tbm=isch&tbo=u&source=univ&ei=tNzqUtqlNsfSyAGd1YCwAQ&ved=0CEcQsAQ&biw=1362&bih=738
looks like it was a 2011 Puyehue-Cordón Caulle eruption in Chile. Some amazing pics: