This video is from the HS.fi news website in Finland and was uploaded today on August 9, 2010. This is Hietaniemi Beach near Helsinki on August 8, 2010, probably around 9 PM (the sky is still light because of the high latitude). The storm cloud is coming from the South and heading North at sea level. Could it be related to the airborne dust particles from the forest fires devastating Russia and fogging up Moscow or from the Icelandic volcano? No other details are available.
This is the only video on Youtube in real time, i.e. without the PAL-to-NTSC 1/24 speed-up, so it is a little longer than the other versions.
A freak storm also ruined a concert by Mötley Cruë and wounded 40 people at the nearby Sonisphere music festival in Pori, Finland, on Sunday August 8, 2010. But Alice Cooper and Iggy Pop did manage to perform afterwards.