Aside from scarring the landscape and altering forest conditions for habitat and healthy streams, clear-cuts pose a greater risk for landowners in the form of mudslides. In 2009, the Seattle Times did an investigation of causes of landslides. Read it here. Keep in mind that Washington's rules for logging are stricter than in Oregon, yet this still happens there.
Scientists have long known that clear-cutting can disrupt the stability of soil and expose hillsides to greater amounts of rainfall, increasing the risk of a catastrophic landslide.
An unfortunate example: the 2007 Woodson, OR debris flow
A December 2007 storm raised these issues in the public eye after a hillside gave way above Highway 30 near Clatskanie. No one was injured, but the small hamlet of Woodson was demolished. Later news reports showed that the slide had been caused by past clear-cut logging in areas above the town.
See a video of aerial footage of the 2007 Woodson mudslide and an exploration of the link between clear-cuts and mudslides: