Expanding Monitoring & Modeling to Assess the Role of Drought in the Persistence of Post-Fire Debris-Flow and Flood Hazards in the Western U.S.

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.

This project has the following objectives:

• Use field measurements to quantify how soil infiltration rates and vegetation/ground cover change as a function of time since burning. 
• Use available products from Climate Engine to determine which (if any) remote sensing product can serve as a proxy for soil recovery and which (if any) can serve as a proxy for vegetation recovery.
• Quantify how and why rainfall intensity-duration thresholds for debris flows vary as a function of time and precipitation patterns (drought) since burning at our study sites. 
• Evaluate the relationship between observed precipitation temporal patterns and departures from normal to changes in infiltration and vegetation at the study sites. Use this information to increase understanding of the role of drought in post-wildfire recovery.
• Communicate results to various partners and relevant regional drought early warning systems (DEWS), as well as the broader scientific community. 
• Make recommendations for the use of remotely sensed products to determine when thresholds are likely to have changed at burned sites. Make suggestions for the development of operational tools for quantifying changes in rainfall ID thresholds as landscapes recover from wildfire, including how they may be modified by drought conditions. 

For more information, please contact Britt Parker (britt.parker@noaa.gov) or Amanda Sheffield (amanda.sheffield@noaa.gov).