Wildfires and Flooding: How Burned Areas Face Increased Flood Risks

Wildfires significantly elevate flood risks in burned areas and downstream regions by removing vegetation and disrupting hydrologic processes. As climate change intensifies both wildfire severity and heavy rainfall events, the likelihood of more severe flooding in the near future is increasing. Understanding how wildfires alter flood risk is critical for disaster preparedness and infrastructure planning in communities nationwide.

Study Methodology: Analyzing Postfire Flooding Patterns

Researchers Canham and Lane analyzed streamflow data from the U.S. Geological Survey’s National Water Information System and precipitation data from the NOAA Analysis of Record for Calibration product. Their goal was to identify storms and quantify their effects across seven burned watersheds in the western United States.

To address limited data on post-wildfire flooding, the team developed a paired-storms framework. This approach involved identifying postfire peak flows (PFPFs), defined as the five highest peak flows within three years of a wildfire across seven watersheds. For each precipitation event causing a PFPF, the researchers then identified paired storms—storms with similar characteristics that occurred before the wildfire. Key storm characteristics used for pairing included:

• Season of occurrence
• Recent precipitation levels
• Precipitation depth, duration, and peak intensity

Key Findings: Elevated Flood Risks After Wildfires

The researchers discovered significantly elevated peak flows following wildfires in many cases, underscoring the heightened risks to communities. Their approach was validated as an effective method for assessing flood risks in burned areas.

In total, the authors identified 26 PFPF events, including 20 with paired storms occurring before wildfires. For 75% of postfire storms, peak flows were at least twice as high as prefire peak flows. The study also found that PFPFs were most likely to occur in the first year after a wildfire. These events typically followed storms that:

• Were centered upstream of the watershed centroid
• Had a uniform shape
• Fully covered the watershed and burned area

The authors also noted that the first storm in the year immediately following a wildfire had a higher-than-expected chance of producing a PFPF.

Future Research Directions

The study suggests future research could explore:

• Storm characteristics over burned areas, such as storm direction and watershed recovery
• Application of automated methods to additional burned watersheds and storm events to enhance the robustness of findings

"Better understanding how, and by how much, wildfires change flood risk is important for disaster and infrastructure planning for communities around the country."

Study Details and Citation

Published in Water Resources Research (DOI: 10.1029/2025WR040693), the study was authored by Canham and Lane. The article was written by Nathaniel Scharping and published in Eos on 30 April 2026.