Monitoring debris flow and flood activity following wildfire: How do drought and vegetation recovery influence post-wildfire hazards?
While there is a strong connection between drought and wildfire in the western United States, how drought influences the post-wildfire environment is less well-understood, especially at shorter (1-3 year) timescales. The hazards posed by post-fire flooding and debris flows in burned landscapes depend on burn severity, underlying geology and topography, and vegetation recovery following the fire. Because vegetation recovery depends on weather and climate conditions, drought may play an important role in controlling the likelihood and magnitude of debris-flow hazards during the recovery process.
Given the links between vegetation, runoff, and erosion, anything that impacts vegetation recovery has the potential to influence the likelihood of post-fire flood and debris flow hazards. Ongoing research aims to use field measurements of soil and vegetation recovery along with computer models to determine the extent to which flooding and debris-flow processes are controlled specifically by vegetation. By quantifying the impact of vegetation on these processes, we can understand how drought and the rate of vegetation recovery influence the amount of time that landscapes remain vulnerable to post-fire hazards. The ultimate goal of this work is to identify relevant drought and vegetation recovery metrics, that can be monitored remotely using data derived from satellites (e.g., Google Climate Engine), to inform how post-fire hazards change with time.