Graph showing the travel time of the mudflow event on the South Fork Toutle River and North Fork Toutle River. Mount St. Helens, Cowlitz County, Washington. 1980.

Index card: Graph showing the travel time of the mudflow event on the South Fork Toutle River and North Fork Toutle River. Note in the mid-range of both forks velocities were comparable. No velocities were collected to the upper reaches of the North Fork Toutle River. Note also the dots which show the travel time for flood event occurring August 27, 1980. Concentration of sediment from the May 18, 1980 mudflows range to 850,000 milligrams per liter, and the concentrations for the August 27, 1980 event ranged to 400,000 milligrams per liter. Travel times through the river reach, however, were not that much different. Cowlitz County, Washington. 1980.