| Abstract: | A well-vegetated 35° slope in upland Wales, U.K., failed during a winter flood event. Failure was linked to high magnitude rainfall and diversion of flowing water onto the slope. Mass movement began with gravitational slumping, which was transformed rapidly into a debris flow. Three-dimensional characteristics of the active debris flow are reconstructed from mudlines on 58 trees still standing in the flow path. Mudline formation only on the up-flow side of trees indicates the relatively high viscosity of the debris flow. Mudline height is a function of the maximum thickness and velocity of the flow at any tree. |
