A large rapid landslide in sensitive glaciomarine sediments at Mink Creek, northwestern British Columbia, Canada

A landslide of 2.5 million m3 of sensitive glaciomarine sediments, predominantly silty clays, occurred at Mink Creek near Terrace, British Columbia (54°27′N, 128°37′W) some time between 1 December 1993 and 9 January 1994. We divide the landslide deposit into seven zones, distinguished on the basis of morphological characteristics. We interpret processes of flowing, spreading and sliding, often in succession, as the landslide retrogressed. The landslide is similar to other movements involving sensitive marine sediments, but is unique in that both flowing and spreading occurred, involving multiple rupture surfaces. Thus the landslide may be classified as a composite earth flow–spread. A decade of warm and wet climate preceded the landslide event. Since most global circulation models predict a warmer and wetter future for Terrace, more of these landslides may be expected.