Mount St Helens, LiDAR image. Mount St Helens is an active volcano (2250 metres summit elevation) in Washington State, USA. The large crater at the top of the volcano, and the barren area around it, were caused by a massive eruption in 1980. LiDAR combines optical and laser imaging to produce digital elevation maps (DEMs), with differences in elevation shown by the colour-coding of the image. Image data from the Washington Lidar Portal of the Washington State Department of Natural Resources, Washington, USA.