Mass of debris, water roars down Nooksack River's middle fork, endangers hikers

In the early hours of May 31, a slurry of mud, trees and boulders - one at least 14 feet across - roared down the middle fork of the Nooksack River.

Called a debris flow by scientists, it would have felt and sounded like a freight train as it rumbled down the river valley for more than 3 miles. Anyone in its path would have been unable to outrun the mass that, at one point, was an estimated 30 feet deep and 150 feet wide. It had the consistency of wet cement.