The boundary between burned and unburned terrain in the area burned by the 2025 Eaton Fire, Angeles National Forest, California. Fire has removed all of the vegetation in the area of the hillslope visible in the image foreground.
Francis Rengers
I investigate landslide and debris flow processes, primarily after wildfire.
General Research Statement:
My work leverages high-resolution topography from airborne and ground-based lidar, as well as drone-based structure-from-motion, to characterize the controls on mass movement after wildfire. I also use modeling and field-instrumentation to characterize how wildfire creates the hydrologic and soil conditions that lead to sedimentation hazards. My work is primarily focused in the semi-arid portions of the Western United States, and I have worked on projects in Australia, New Zealand, and Sri Lanka. In addition, I serve as an adjunct professor at the Colorado School of Mines, I advise USGS post-docs, and I am currently serving on Ph.D. thesis committees at several universities.
Education:
- Ph.D., Geology, University of Colorado, Boulder, CO. 2014. The Influence of Transient Perturbations on Landscape Evolution: Exploring Gully Erosion and Post-Wildfire Erosion.
- M. S., Geology, Colorado State University, Fort Collins, CO. 2005. Grain Size Trends of Gravel Bars on the Rio Chagres, Panama
- B. S., Geology, Summa Cum Laude, West Virginia University, Morgantown, WV. 2003. Spatial Analysis of Landforms on Reclaimed Surface Mines of Monongalia County
- B. A., French, Summa Cum Laude, West Virginia University, Morgantown, WV. 2003
Professional Appointments:
2016-present Research Geologist
2014-2016 Mendenhall Postdoctoral Research Fellow
Staley, D.M., Kean, J.W., Rengers, F.K. 2020. The recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States. Geomorphology. https://doi.org/10.1016/j.geomorph.2020.107392
Rengers, F.K., McGuire, L.A., Oakley, N.S., Tang, H., Kean, J.W., and Staley, D.M. 2020. Landslides after Wildfire: initiation, magnitude, and mobility after fire. Landslides. https://doi.org/10.1007/s10346-020-01506-3
Rengers, F.K., Kean, J.W., Reitman, N.G., Smith, J.B., Coe, J.A., McGuire, L.A., 2020. The Influence of Frost Weathering on Debris Flow Sediment Supply in an Alpine Basin. Journal of Geophysical Research: Earth Surface 125, e2019JF005369. https://doi.org/10.1029/2019JF005369
Wall, S., Roering, J., Rengers, F.K., 2020. Runoff-initiated post-fire debris flow Western Cascades, Oregon. Landslides. https://doi.org/10.1007/s10346-020-01376-9
Rapstine, T.D., Rengers, F.K., Allstadt, K.E., Iverson, R.M., Smith, J.B., Obryk, M.K., Logan, M. Olsen, M.J. 2020. Reconstructing the velocity and deformation of a rapid landslide using multiview video. Journal of Geophysical Research: Earth Surface. https://doi.org/10.1029/2019JF005348
Kean, Jason W., Staley, D.M., Lancaster, J.T., Rengers, F.K., Swanson, B.J., Coe, J.A., Hernandez, J.L., Sigman, A.J., Allst
Science and Products
Landslide Assessments, Situational Awareness, and Event Response Research (LASER)
Landslide crises can unfold in many ways, but in all cases, responders and the public need information about what happened and what might happen next as soon as possible. The LASER project seeks to provide event-driven information products and assessments for landslide events to help guide decision-making and inform the public. The project also conducts research and development aimed towards...
Columbia River Gorge Landslides
Extreme rainfall during two atmospheric river events in January 2021 and January 2022 triggered a series of debris flows in the Columbia River Gorge, Oregon. The flows had significant impacts, including multiple highway closures and one fatality. This story map highlights rainfall data and observations of debris flow deposits by the Oregon Department of Geology and Mineral Industries (DOGAMI)...
Cameron Peak, Colorado, Fire: Flooding and Debris Flows - July 20, 2021
On Thursday, August 13, 2020, at approximately 1:45 PM MDT, the Cameron Peak fire was reported in steep, rugged terrain 15 miles southwest of Red Feather Lakes, Colorado, near Cameron Pass. The fire spread rapidly due to extreme temperatures, strong winds, and high fuel loads. The largest wildfire in Colorado history, the Cameron Peak fire burned 845 square kilometers (sq km) on the Arapaho and...
Glenwood Canyon, Colorado, Flooding and Debris Flows: 2021
Summer storms on the Grizzly Creek burn area have resulted in repeated flooding and debris flows that are having enormous impacts in Glenwood Canyon. This Story Map collection summarizes the June and July events.
Bond Fire Debris Flows, California: January 25 and 28, 2021
On Wednesday, December 2, 2020 at approximately 10:15 PM PST, the Bond wildfire ignited in Orange County, California, burning partially within the Cleveland Forest, near Silverado Canyon just north of the area burned by the October 2020 Silverado fire. The fire burned 27 square kilometers (sq km) prior to containment on December 10, 2020 (CalFire). Fuels were primarily chaparral, brush, and tall...
Northern and Central California Debris Flows - January 2021
An atmospheric river (AR) moved into California late on the evening of January 26, 2021, bringing intermittent heavy rainfall that resulted in flooding, debris flows, and heavy snowfall at high elevations.
Tadpole Fire Debris Flows, New Mexico: July and September 2020
On Saturday, June 6, 2020 at approximately 1:45 PM MDT, the Tadpole wildfire ignited in the Gila National Forest, approximately 19 kilometers (km) north of Silver City, Grant County, New Mexico. The fire burned 45 square kilometers prior to containment in early July, 2020 (Inciweb). Fuels were primarily timber with grass understory, brush, and chaparral. The Brush, Bringham, and Bighorn fires in...
Woodbury Fire, Arizona Debris Flows - September 2019
On Saturday, June 8, 2019 at approximately 1:30 PM MST, the Woodbury wildfire ignited approximately 8 kilometers (km) northwest of Superior, Arizona. The 7th largest wildfire in Arizona’s recorded history, the fire burned 501 km2 prior to containment on July 15, 2019. The fire occurred within the Superstition Wilderness of the Tonto National Forest. The wilderness area extends from the...
Calwood Fire "Heil Ranch" Landslide Monitoring Site near Boulder, CO
Wildfire can radically change a mountainous landscape such that even a modest rainstorm is capable of producing deadly and destructive flash flooding and debris flows.
Advancing Post-Fire Debris Flow Hazard Science with a Field Deployable Mapping Tool
Mapping the occurrence of post-fire flooding and debris flow is crucial for 1) integrating observations into models used to define rainfall thresholds for early warning, 2) understanding patterns of inundation, and 3) improving models for predictive hazard assessment. Despite the critical role mapping plays in post-fire hazard assessment and early warning, there has not been a...
How Often Do Rainstorms Cause Debris Flows in Burned Areas of the Southwestern U.S.?
Debris flows, sometimes referred to as mudslides, mudflows, lahars, or debris avalanches, are common types of fast-moving landslides. They usually start on steep hillsides as a result of shallow landslides, or from runoff and erosion that liquefy and accelerate to speeds in excess of 35 mi/h. The consistency of debris flows ranges from thin, watery to thick, rocky mud that can carry large items...
Exploiting high-resolution topography for advancing the understanding of mass and energy transfer across landscapes: Opportunities, challenges, and needs
One of the grand challenges of Earth Surface Science and Natural Resource Management lies in the prediction of mass and energy transfer for large watersheds and landscapes. High resolution topography (lidar) datasets show potential to significantly advance our understanding of hydrologic and geomorphic processes controlling mass and energy transfer because they represent features at the...
Burned and unburned hillslopes, Eaton Fire, California
The boundary between burned and unburned terrain in the area burned by the 2025 Eaton Fire, Angeles National Forest, California. Fire has removed all of the vegetation in the area of the hillslope visible in the image foreground.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northwestern edge of the burn perimeter, just off of Sunset Ridge road. High winds while the fire burned and after it was contained has removed ash from the hillside.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northwestern edge of the burn perimeter, just off of Sunset Ridge road. High winds while the fire burned and after it was contained has removed ash from the hillside.
Soil property measurements in the Eaton Fire burn area, Angeles National Forest, California
Soil property measurements in the Eaton Fire burn area, Angeles National Forest, California. A scientist uses a Mini Disk infiltrometer to measure how fast water infiltrates the ground's surface in the 2025 Eaton Fire burn area. Infiltrometer measurements help determine soil burn severity.
Soil property measurements in the Eaton Fire burn area, Angeles National Forest, California. A scientist uses a Mini Disk infiltrometer to measure how fast water infiltrates the ground's surface in the 2025 Eaton Fire burn area. Infiltrometer measurements help determine soil burn severity.
West Ravine debris basin in Los Angeles County, California on January 20, 2025.
The West Ravine debris basin in Los Angeles County, California on January 20, 2024. The debris basin is mostly empty, with remnants of debris being cleared by a front loader and dump truck. This photograph was taken following the 2025 Eaton wildfire and prior to any rainfall over the burn area.
The West Ravine debris basin in Los Angeles County, California on January 20, 2024. The debris basin is mostly empty, with remnants of debris being cleared by a front loader and dump truck. This photograph was taken following the 2025 Eaton wildfire and prior to any rainfall over the burn area.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northern edge of the burn perimeter off of Echo Mountain Low Fire Road. Unburned, vegetated terrain is visible in the image background. This photo was taken shortly after the Eaton Fire was contained.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northern edge of the burn perimeter off of Echo Mountain Low Fire Road. Unburned, vegetated terrain is visible in the image background. This photo was taken shortly after the Eaton Fire was contained.
Dry ravel in the 2025 Eaton Fire burn area.
A detailed look at a hillslope within the Eaton Fire burn area showing sediment particles, visible in the foreground, moving downslope. Remnants of burned trees and other vegetation are also visible on the hillslope.
A detailed look at a hillslope within the Eaton Fire burn area showing sediment particles, visible in the foreground, moving downslope. Remnants of burned trees and other vegetation are also visible on the hillslope.
Virtual Field Excursion to Glenwood Canyon, Colorado: and the post-fire debris flows from the 2020 Grizzly Creek Fire
linkThis video serves as a virtual fieldtrip to document the debris flow activity following the Grizzly Creek Fire in the Glenwood Canyon, CO, USA. The Grizzly Creek Fire initiated in August 2020, and widespread destructive debris flow activity followed the during the summer of 2021.
Virtual Field Excursion to Glenwood Canyon, Colorado: and the post-fire debris flows from the 2020 Grizzly Creek Fire
linkThis video serves as a virtual fieldtrip to document the debris flow activity following the Grizzly Creek Fire in the Glenwood Canyon, CO, USA. The Grizzly Creek Fire initiated in August 2020, and widespread destructive debris flow activity followed the during the summer of 2021.
Calwood Fire, Heil Ranch post-fire debris-flow monitoring station, July 31, 2021
Calwood burn area, Heil Ranch post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:07 MDT to 14:13:11 MDT.
Calwood burn area, Heil Ranch post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:07 MDT to 14:13:11 MDT.
Calwood Fire, Calwood post-fire debris-flow monitoring station, July 31, 2021
Calwood burn area, Calwood post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:06 MDT to 14:13:05 MDT.
Calwood burn area, Calwood post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:06 MDT to 14:13:05 MDT.
Aerial view of Eaton Wash and Eaton Wash dam
Eaton Wash (blue arrow) is a channel that flows along the mountain front and empties into the Eaton Wash Reservoir (red arrow). The Eaton Wash Dam and Eaton Wash Reservoir help to control flood waters and trap sediment that shed from the range front during the rainy season in southern California.
Eaton Wash (blue arrow) is a channel that flows along the mountain front and empties into the Eaton Wash Reservoir (red arrow). The Eaton Wash Dam and Eaton Wash Reservoir help to control flood waters and trap sediment that shed from the range front during the rainy season in southern California.
Science and Products
Landslide Assessments, Situational Awareness, and Event Response Research (LASER)
Landslide crises can unfold in many ways, but in all cases, responders and the public need information about what happened and what might happen next as soon as possible. The LASER project seeks to provide event-driven information products and assessments for landslide events to help guide decision-making and inform the public. The project also conducts research and development aimed towards...
Columbia River Gorge Landslides
Extreme rainfall during two atmospheric river events in January 2021 and January 2022 triggered a series of debris flows in the Columbia River Gorge, Oregon. The flows had significant impacts, including multiple highway closures and one fatality. This story map highlights rainfall data and observations of debris flow deposits by the Oregon Department of Geology and Mineral Industries (DOGAMI)...
Cameron Peak, Colorado, Fire: Flooding and Debris Flows - July 20, 2021
On Thursday, August 13, 2020, at approximately 1:45 PM MDT, the Cameron Peak fire was reported in steep, rugged terrain 15 miles southwest of Red Feather Lakes, Colorado, near Cameron Pass. The fire spread rapidly due to extreme temperatures, strong winds, and high fuel loads. The largest wildfire in Colorado history, the Cameron Peak fire burned 845 square kilometers (sq km) on the Arapaho and...
Glenwood Canyon, Colorado, Flooding and Debris Flows: 2021
Summer storms on the Grizzly Creek burn area have resulted in repeated flooding and debris flows that are having enormous impacts in Glenwood Canyon. This Story Map collection summarizes the June and July events.
Bond Fire Debris Flows, California: January 25 and 28, 2021
On Wednesday, December 2, 2020 at approximately 10:15 PM PST, the Bond wildfire ignited in Orange County, California, burning partially within the Cleveland Forest, near Silverado Canyon just north of the area burned by the October 2020 Silverado fire. The fire burned 27 square kilometers (sq km) prior to containment on December 10, 2020 (CalFire). Fuels were primarily chaparral, brush, and tall...
Northern and Central California Debris Flows - January 2021
An atmospheric river (AR) moved into California late on the evening of January 26, 2021, bringing intermittent heavy rainfall that resulted in flooding, debris flows, and heavy snowfall at high elevations.
Tadpole Fire Debris Flows, New Mexico: July and September 2020
On Saturday, June 6, 2020 at approximately 1:45 PM MDT, the Tadpole wildfire ignited in the Gila National Forest, approximately 19 kilometers (km) north of Silver City, Grant County, New Mexico. The fire burned 45 square kilometers prior to containment in early July, 2020 (Inciweb). Fuels were primarily timber with grass understory, brush, and chaparral. The Brush, Bringham, and Bighorn fires in...
Woodbury Fire, Arizona Debris Flows - September 2019
On Saturday, June 8, 2019 at approximately 1:30 PM MST, the Woodbury wildfire ignited approximately 8 kilometers (km) northwest of Superior, Arizona. The 7th largest wildfire in Arizona’s recorded history, the fire burned 501 km2 prior to containment on July 15, 2019. The fire occurred within the Superstition Wilderness of the Tonto National Forest. The wilderness area extends from the...
Calwood Fire "Heil Ranch" Landslide Monitoring Site near Boulder, CO
Wildfire can radically change a mountainous landscape such that even a modest rainstorm is capable of producing deadly and destructive flash flooding and debris flows.
Advancing Post-Fire Debris Flow Hazard Science with a Field Deployable Mapping Tool
Mapping the occurrence of post-fire flooding and debris flow is crucial for 1) integrating observations into models used to define rainfall thresholds for early warning, 2) understanding patterns of inundation, and 3) improving models for predictive hazard assessment. Despite the critical role mapping plays in post-fire hazard assessment and early warning, there has not been a...
How Often Do Rainstorms Cause Debris Flows in Burned Areas of the Southwestern U.S.?
Debris flows, sometimes referred to as mudslides, mudflows, lahars, or debris avalanches, are common types of fast-moving landslides. They usually start on steep hillsides as a result of shallow landslides, or from runoff and erosion that liquefy and accelerate to speeds in excess of 35 mi/h. The consistency of debris flows ranges from thin, watery to thick, rocky mud that can carry large items...
Exploiting high-resolution topography for advancing the understanding of mass and energy transfer across landscapes: Opportunities, challenges, and needs
One of the grand challenges of Earth Surface Science and Natural Resource Management lies in the prediction of mass and energy transfer for large watersheds and landscapes. High resolution topography (lidar) datasets show potential to significantly advance our understanding of hydrologic and geomorphic processes controlling mass and energy transfer because they represent features at the...
Burned and unburned hillslopes, Eaton Fire, California
The boundary between burned and unburned terrain in the area burned by the 2025 Eaton Fire, Angeles National Forest, California. Fire has removed all of the vegetation in the area of the hillslope visible in the image foreground.
The boundary between burned and unburned terrain in the area burned by the 2025 Eaton Fire, Angeles National Forest, California. Fire has removed all of the vegetation in the area of the hillslope visible in the image foreground.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northwestern edge of the burn perimeter, just off of Sunset Ridge road. High winds while the fire burned and after it was contained has removed ash from the hillside.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northwestern edge of the burn perimeter, just off of Sunset Ridge road. High winds while the fire burned and after it was contained has removed ash from the hillside.
Soil property measurements in the Eaton Fire burn area, Angeles National Forest, California
Soil property measurements in the Eaton Fire burn area, Angeles National Forest, California. A scientist uses a Mini Disk infiltrometer to measure how fast water infiltrates the ground's surface in the 2025 Eaton Fire burn area. Infiltrometer measurements help determine soil burn severity.
Soil property measurements in the Eaton Fire burn area, Angeles National Forest, California. A scientist uses a Mini Disk infiltrometer to measure how fast water infiltrates the ground's surface in the 2025 Eaton Fire burn area. Infiltrometer measurements help determine soil burn severity.
West Ravine debris basin in Los Angeles County, California on January 20, 2025.
The West Ravine debris basin in Los Angeles County, California on January 20, 2024. The debris basin is mostly empty, with remnants of debris being cleared by a front loader and dump truck. This photograph was taken following the 2025 Eaton wildfire and prior to any rainfall over the burn area.
The West Ravine debris basin in Los Angeles County, California on January 20, 2024. The debris basin is mostly empty, with remnants of debris being cleared by a front loader and dump truck. This photograph was taken following the 2025 Eaton wildfire and prior to any rainfall over the burn area.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northern edge of the burn perimeter off of Echo Mountain Low Fire Road. Unburned, vegetated terrain is visible in the image background. This photo was taken shortly after the Eaton Fire was contained.
A steep, burned hillside in the 2025 Eaton Fire, Los Angeles County, California. The hillside is located near the northern edge of the burn perimeter off of Echo Mountain Low Fire Road. Unburned, vegetated terrain is visible in the image background. This photo was taken shortly after the Eaton Fire was contained.
Dry ravel in the 2025 Eaton Fire burn area.
A detailed look at a hillslope within the Eaton Fire burn area showing sediment particles, visible in the foreground, moving downslope. Remnants of burned trees and other vegetation are also visible on the hillslope.
A detailed look at a hillslope within the Eaton Fire burn area showing sediment particles, visible in the foreground, moving downslope. Remnants of burned trees and other vegetation are also visible on the hillslope.
Virtual Field Excursion to Glenwood Canyon, Colorado: and the post-fire debris flows from the 2020 Grizzly Creek Fire
linkThis video serves as a virtual fieldtrip to document the debris flow activity following the Grizzly Creek Fire in the Glenwood Canyon, CO, USA. The Grizzly Creek Fire initiated in August 2020, and widespread destructive debris flow activity followed the during the summer of 2021.
Virtual Field Excursion to Glenwood Canyon, Colorado: and the post-fire debris flows from the 2020 Grizzly Creek Fire
linkThis video serves as a virtual fieldtrip to document the debris flow activity following the Grizzly Creek Fire in the Glenwood Canyon, CO, USA. The Grizzly Creek Fire initiated in August 2020, and widespread destructive debris flow activity followed the during the summer of 2021.
Calwood Fire, Heil Ranch post-fire debris-flow monitoring station, July 31, 2021
Calwood burn area, Heil Ranch post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:07 MDT to 14:13:11 MDT.
Calwood burn area, Heil Ranch post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:07 MDT to 14:13:11 MDT.
Calwood Fire, Calwood post-fire debris-flow monitoring station, July 31, 2021
Calwood burn area, Calwood post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:06 MDT to 14:13:05 MDT.
Calwood burn area, Calwood post-fire debris-flow monitoring station video footage from rainstorm on July 31, 2021 from 14:06 MDT to 14:13:05 MDT.
Aerial view of Eaton Wash and Eaton Wash dam
Eaton Wash (blue arrow) is a channel that flows along the mountain front and empties into the Eaton Wash Reservoir (red arrow). The Eaton Wash Dam and Eaton Wash Reservoir help to control flood waters and trap sediment that shed from the range front during the rainy season in southern California.
Eaton Wash (blue arrow) is a channel that flows along the mountain front and empties into the Eaton Wash Reservoir (red arrow). The Eaton Wash Dam and Eaton Wash Reservoir help to control flood waters and trap sediment that shed from the range front during the rainy season in southern California.