Digital elevation model of Mount St. Helens, Washington and vicinity prior to the 1980 eruption

On May 18, 1980, Mount St. Helens, Washington, exploded in a spectacular and devastating eruption that resulted in previously unimaginable events that drastically altered the mountain and the surrounding area. One unprecedented event was the collapse of the summit and north flank of the volcano forming a huge landslide known as the ‘debris avalanche’ with a total volume of about 2.5 km3 (3.3 billion cubic yards). The debris avalanche swept around and up ridges to the north, but most of it turned westward as far as 23 km (14 mi) down the valley of the North Fork Toutle River and formed a hummocky deposit. This had a profound effect on the topography of the area, including transforming the summit cone of the volcano into an amphitheater-shaped [...]