Digital elevation models of upper North Fork Toutle River near Mount St. Helens, based on 2006-2014 airborne lidar surveys

The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980-1986 and 2004-2008. Nearly four decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the North Fork Toutle River basin, which drains the northern flank of the volcano. This high sediment production poses a risk of flooding to downstream communities along the Toutle and Cowlitz Rivers and of clogging the shipping channel of the Columbia River. Consequently, U.S. Army Corps of Engineers (USACE), under the direction of Congress, built a sediment retention structure [...]