High-severity wildfires can increase runoff and erosion rates by one or more orders of magnitude, and these increases can threaten life and property as well as severely degrading water quality and aquatic ecosystems. Each year millions of dollars are spent on emergency postfire rehabilitation treatments to minimize flood runoff and soil erosion. Few data have been available to systematically evaluate the effectiveness of these treatments over time, much less understand why the different treatments might vary in their effectiveness. There also is an urgent need to develop and test models for predicting post-fire erosion and the likely effects of different post-fire treatments. In response to these needs, we initiated a series of detailed studies after the 2002 wildfires in Colorado.