Landslides and landslide hazards in Washington State due to the February 5-9, 1996 storm

Debris flows were the most common landslide type triggered by the February
5-9 storm. Debris flows typically originate within soil overlying bedrock.
Other types of landslides observed were rotational slumps, block slides, rock falls, soil slides, and soil falls. The largest landslide triggered by the February storm was a block slide of 100,000 to 200,000 yd3 that became fluidized by mixing and transformed into a debris flow. This landslide
is discussed in the section on the Glenoma landslide.