Young River Landslide
On 27 August 2007 at 4:40 am a landslide of about 13 million cubic metres of schist dammed the north branch of the Young River in the Southern Alps of New Zealand creating a lake upstream of the debris fan. The first two images here are from Google Earth (44.143S 169.124E), the third is from flashearth.
More details of the landslide from Dave Petley's Landslide Blog, and a GNS Science poster (warning pdf).