Lessons learned from the local calibration of a debris flow model and importance to a geohazard assessment

Post-wildfire debris flows are a common hazard in many locales throughout the world. There is a demand for predicting the runout, inundation, and probability of occurrence to educate property owners, inform mitigation, and local planning in the wildland urban interface. Here, we calibrate our model to debris flow that occurred outside of a recent project area.

The model can accurately predict the runout, including an avulsion that took place on the alluvial fan and the spatial extent of other surges that extended across much of the alluvial fan. The model was also able to predict the flow depths that could be used to account for the loss of homes at the debris flow site. Not only is modeling and our approach a critical tool in geohazard assessments after a wildfire, but it could also be used as a more proactive tool for planning and mitigation for debris flows in current and future development that would make our communities more resilient.