Radar Reveals How Long-Range Embers Fueled California’s Deadliest Wildfire

The 2018 Camp Fire remains California’s deadliest and most destructive wildfire on record. Its explosive growth was driven by strong winds, dry fuels, and a phenomenon known as organized long-range spotting—the lofting and downwind fallout of burning embers that ignite new fires far ahead of the main fire front.

In a new study published in the Journal of Geophysical Research: Atmospheres, researcher Neil P. Lareau [2026] provides the first high-resolution depiction of spotting behavior during an extreme wildfire using operational Doppler radar and satellite observations. The findings reveal that spot fire events for the Camp Fire occurred 5–10 kilometers ahead of the fire front, quickly merging into new fire lines.

Crucially, these spot fires were not randomly distributed. Instead, they aligned within coherent fallout zones shaped by plume dynamics and background winds. This discovery demonstrates that operational weather radar can identify lofting and fallout regions in real time, offering a new method to anticipate spotting-driven fire spread and improve early warnings for fast-moving wildfires.

Key Observations from the Study

• Spot fire events occurred 5–10 km ahead of the main fire front.
• Spot fires merged rapidly into new fire lines, accelerating the fire’s spread.
• Spot fires were aligned within coherent fallout zones influenced by plume dynamics and wind patterns.
• Operational weather radar can detect lofting and fallout regions in real time, enabling earlier warnings.

Visual Evidence: Radar and Satellite Data

The study includes detailed radar and satellite imagery illustrating the Camp Fire’s plume dynamics and fire progression. Key figures include:

• (a) An along-wind cross section of the Camp Fire plume reflectivity observed by radar, showing distinct updrafts (white arrows) and ashfall regions (blue dashed arrow). Spot fires within 10 minutes of these radar measurements are marked as filled cyan triangles.
• (b) A map of column maximum radar reflectivity and fire perimeter, with the eastern edge of Paradise, California, indicated by a black dashed line.

Study Citation

Lareau, N. P. (2026). Plume-coupled long-range spotting drove the explosive spread of the 2018 Camp Fire. Journal of Geophysical Research: Atmospheres, 131, e2025JD045798. https://doi.org/10.1029/2025JD045798

—William Randel, Editor, JGR: Atmospheres

© 2026. The authors. CC BY-NC-ND 3.0. Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.