Article
Environmental Sciences
Anping Shu, Le Wang, Fuyang Zhu, Jiapin Zhu, Chengling Pi, Ziru Zhang, Huarez Christian
Summary: This study focuses on the hydro-sediment dynamic processes that control unconsolidated dam failure and subsequent debris flow. Experimental results show that debris flows induced by partial dam failures are likely to occur under low overtopping flow and shallow channel slope conditions, while debris flows originated from en masse dam failures develop well under the opposite conditions. The critical shear stresses for sediment entrainment under en masse dam failure cases are generally higher compared to partial dam-failure equivalents. The relative proportion of clear water to erodible solid materials is also related to the dam failure mode, which ultimately determines debris-flow properties.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Luke A. McGuire, Ann M. Youberg, Francis K. Rengers, Nathan S. Abramson, Indujaa Ganesh, Alexander N. Gorr, Olivia Hoch, Justin C. Johnson, Patt Lamom, Alexander B. Prescott, Jessica Zanetell, Brendan Fenerty
Summary: In steep landscapes, wildfire-induced changes to soil and vegetation can lead to extreme and hazardous geomorphic responses, including debris flows. Factors such as regional climate, vegetation, soil texture, and soil burn severity play a significant role in determining the heightened geomorphic responses post-wildfire. The study highlights the differences in debris flows between burned and unburned areas, providing insights into the impact of wildfires on geomorphic processes in steep terrain.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Geosciences, Multidisciplinary
Xichao Cao, Xiewen Hu, Mei Han, Tao Jin, Xiangbin Yang, Ying Yang, Kun He, Yan Wang, Jian Huang, Chuanjie Xi, Bo Liu
Summary: This study analyzed post-fire hillslope erosion using various methods, developed a predictive model, and evaluated the model performance. The results show that fire severity, soil properties, rainfall, and topography are the main factors affecting hillslope erosion, and the new predictive model has a good performance.
Article
Geography, Physical
Alexander B. Neely, Roman A. DiBiase
Summary: Steep channel networks typically transition from constant-gradient colluvial channels associated with debris flow activity to concave-up fluvial channels downstream. However, the trade-off between debris flow and fluvial erosion in steep channels remains unclear and obscures connections among topography, tectonics, and climate in steep landscapes. Through analysis and observation of steep debris-flow-prone channels across the western United States, it has been found that steep channel gradients are controlled by two competing thresholds of motion for bed-sediment cover: bed failure by mass-wasting and fluvial entrainment. This study highlights the importance of understanding the sensitivity of fluvial and debris flow processes to sediment grain size and its impact on the relief of colluvial and fluvial regimes in headwater channel networks.
EARTH SURFACE PROCESSES AND LANDFORMS
(2023)
Article
Geography, Physical
Haruka Tsunetaka, Norifumi Hotta, Fumitoshi Imaizumi, Yuichi S. Hayakawa, Takeshi Masui
Summary: This study explored the relationship between rainfall patterns and sediment storage changes in triggering debris flows. Field-based monitoring in Japan revealed that longer consecutive periods of rainfall above threshold tended to trigger debris flows, but sediment discharge and recharge cycles also played a role in changing the rainfall threshold required for debris-flow occurrences.
Article
Geography, Physical
Sara Wall, Brendan P. Murphy, Patrick Belmont, Larissa Yocom
Summary: This study aims to address two key limitations in predicting post-fire debris flows: accurate volume prediction without triggering storm rainfall intensities and understanding controls on grain sizes. The researchers compiled and analyzed a dataset of depositional volumes and grain size distributions for 59 post-fire debris flows and developed a new prediction model. The study found that topography, burn severity, and pre-fire soil organic matter percentage were important variables in predicting debris flow volumes. The study also constructed models to predict different grain sizes produced by post-fire debris flows. The results enhance our ability to predict the transportation of post-fire sediment pulses through watersheds.
EARTH SURFACE PROCESSES AND LANDFORMS
(2023)
Article
Environmental Sciences
Zheng Han, Ming Li, Yange Li, Mingyue Zhao, Changli Li, Wendu Xie, Haohui Ding, Yangfan Ma
Summary: Recent studies have shown that accurate simulation of debris flows relies not only on numerical models, but also on precise data on source location and depth. Obtaining quantitative data on source locations and depths is currently difficult. In this study, we propose an integrated approach that includes a physically based slope initiation source estimation and entrainment-incorporated process simulation. By treating potential slip surfaces as random variables and using Monte Carlo simulation, we search for the critical surface corresponding to the minimum stability factor. We also propose a wet/dry front treatment method to improve the stability and accuracy of the numerical solution over complex topography.
Article
Engineering, Environmental
Arpita Mandal, Arpita Nandi, Abdul Shakoor, Jeffrey Keaton
Summary: This study compares gauge and radar data to simulate infiltration and analyze debris flow occurrence in remote areas of the Great Smoky Mountains National Park in Tennessee. The results show that weather radar is a valuable tool for estimating rainfall intensity, duration, runoff, and infiltration.
ENVIRONMENTAL & ENGINEERING GEOSCIENCE
(2022)
Article
Engineering, Geological
Hao-Jie Li, Hong-Hu Zhu, Yuan-Hai Li, Wei Hu, Bin Shi
Summary: A flume test was conducted on soil samples from a debris flow site in the Wenchuan earthquake area to explore the initiation of landslide-debris flow caused by concentrated runoff. The fiber Bragg grating (FBG) technology showed high sensitivity and precision in monitoring slope deformation, indicating its enormous potential in establishing an effective early warning system for landslides and debris flows.
GEOTECHNICAL TESTING JOURNAL
(2021)
Editorial Material
Geography, Physical
F. K. Rengers, Luke A. McGuire
Summary: Wildfire is a landscape-scale disturbance that affects the rate and magnitude of earth surface processes, with impacts varying depending on site-specific conditions. Studying the effects of fire on earth surface processes helps scientists and land managers better predict and manage the negative impacts of wildfires.
EARTH SURFACE PROCESSES AND LANDFORMS
(2021)
Article
Engineering, Geological
Sujana Timilsina, Jeffrey D. Niemann, Sara L. Rathburn, Francis K. Rengers, Peter A. Nelson
Summary: During a seven-day extreme rainfall event in September 2013 in the Colorado Front Range, it was observed that south-facing slopes were more prone to experiencing debris flows compared to north-facing slopes. By analyzing soil moisture patterns and hydrologic processes, it was determined that differences in interception and deep drainage were the primary factors leading to the saturation of south-facing slopes. The final model predicted instability at around 72% of observed debris flow initiation sites.
Article
Engineering, Environmental
Luke A. Mcguire, Francis K. Rengers, Nina Oakley, Jason W. Kean, Dennis M. Staley, Hui Tang, Marian de Orla-Barile, Ann M. Youberg
Summary: The study combines measurements of soil-hydraulic properties with vegetation survey data and numerical modeling to predict changes in debris-flow properties and initiation thresholds in steep, burned watersheds following wildfires. Numerical modeling suggests that the intensity-duration threshold for debris flows varies depending on rainfall distribution within a storm, and that debris-flow volumes are significantly reduced after 1 year of recovery. Moreover, the threshold for debris flows increases from post-fire year 1 to year 3 in the San Gabriel Mountains region.
ENVIRONMENTAL & ENGINEERING GEOSCIENCE
(2021)
Article
Environmental Sciences
Jason W. Kean, Dennis M. Staley
Summary: Southern California has a long history of damaging debris flows after wildfires, but forecasts of the frequency and magnitude of postfire debris flows are not as readily available as they are for earthquakes. Research shows that small debris flows can be expected almost every year, while major debris flows capable of damaging 40 or more structures have a recurrence interval between 10 and 13 years.
Article
Geosciences, Multidisciplinary
Luke A. McGuire, Ann M. Youberg, Francis K. Rengers, Nathan S. Abramson, Indujaa Ganesh, Alexander N. Gorr, Olivia Hoch, Justin C. Johnson, Patt Lamom, Alexander B. Prescott, Jessica Zanetell, Brendan Fenerty
Summary: In steep landscapes, wildfire-induced changes to soil and vegetation can lead to extreme and hazardous geomorphic responses, including debris flows. Factors such as regional climate, vegetation, soil texture, and soil burn severity play a significant role in determining the heightened geomorphic responses post-wildfire. The study highlights the differences in debris flows between burned and unburned areas, providing insights into the impact of wildfires on geomorphic processes in steep terrain.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Water Resources
Tao Liu, Luke A. McGuire, Haiyan Wei, Francis K. Rengers, Hoshin Gupta, Lin Ji, David C. Goodrich
Summary: This study uses a hydrological model to investigate the changes in hydraulic parameters following a wildfire in the Arroyo Seco watershed in California. Results show that saturated hydraulic conductivity is lowest in the first year post-fire and increases at an average rate of about 4.2 mm/h/year during the first 5 years of recovery. Channel hydraulic roughness was lowest in the first year post-fire, but doubled after one year of recovery, with changes related to grain roughness and vegetation in channels.
HYDROLOGICAL PROCESSES
(2021)
Article
Geosciences, Multidisciplinary
Matthew A. Thomas, Francis K. Rengers, Jason W. Kean, Luke A. McGuire, Dennis M. Staley, Katherine R. Barnhart, Brian A. Ebel
Summary: This study analyzes the potential for debris flows after wildfires over time and proposes a method to improve awareness of post-wildfire debris flow hazards. The research finds that rainfall intensity and duration are closely related to the types of debris flows following wildfires, while factors such as soil moisture, rainfall climatology, and root reinforcement may also impact the probability of debris flows.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Geosciences, Multidisciplinary
F. K. Rengers, Luke A. McGuire, Jason W. Kean, Dennis M. Staley, Mariana Dobre, Peter R. Robichaud, Tyson Swetnam
Summary: Post-wildfire changes in sediment redistribution were measured using terrestrial and airborne lidar in the San Gabriel Mountains in southern California. The study found that hillslope erosion dominated the overall sediment budget in the first rainy season after the wildfire, and post-wildfire erosion rates in the area were comparable to millennial time scale bedrock erosion rates.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Geosciences, Multidisciplinary
K. R. Barnhart, R. P. Jones, D. L. George, B. W. McArdell, F. K. Rengers, D. M. Staley, J. W. Kean
Summary: The study focused on hazard assessment for post-wildfire debris flows in steep terrain, emphasizing the importance of reducing uncertainty in pre-event estimates of flow volume. Three debris flow runout models were tested using observations from the 2018 Montecito event, showing that model performance was most sensitive to flow volume and less sensitive to flow properties. This highlights the significance of accurately estimating flow volume for effective hazard assessment.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Engineering, Geological
Alexander N. Gorr, Luke A. McGuire, Ann M. Youberg, Francis K. Rengers
Summary: The study presents a computationally efficient debris-flow inundation model, ProDF, calibrated using data from five watersheds near Montecito, California to demonstrate its effectiveness in simulating debris-flow inundation.
Review
Geosciences, Multidisciplinary
Timothy Titus, D. Robertson, J. B. Sankey, L. Mastin, F. Rengers
Summary: Modern civilization lacks collective experience in dealing with the potential wide-ranging effects of a medium-sized asteroid impact. While efforts have been made to model the initial effects of meteor impacts or airbursts, the long-term cascading hazards are often overlooked. This paper reviews the initial and cascading effects of more common natural disasters and discusses their relevance to the expected long-term effects of an asteroid impact. A framework linking multiple hazard models could greatly benefit emergency managers, resource planners, and research scientists involved in mitigation and recovery efforts.
Article
Astronomy & Astrophysics
Ryan P. P. Jones, Francis K. K. Rengers, Katherine R. R. Barnhart, David L. L. George, Dennis M. M. Staley, Jason W. W. Kean
Summary: Debris flow runout is a dangerous phenomenon that poses risks to human life and infrastructure. By modifying a flow model to include the effects of segregation on permeability, we found that it improved the accuracy of predicting debris flow depth and runout distance. Therefore, considering segregation is important in predicting and mitigating debris flow hazards.
EARTH AND SPACE SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Matthew A. A. Thomas, Donald N. N. Lindsay, David B. B. Cavagnaro, Jason W. W. Kean, Scott W. W. McCoy, Andrew P. P. Graber
Summary: Increased wildfire activity in the western United States has revealed gaps in understanding postfire debris-flow generation. By characterizing flows in an unstudied area, we found that short-duration, high-intensity rainfall is more likely to initiate runoff-generated debris flows compared to total storm rainfall. This finding suggests the need for a focus on localized thunderstorms or bands of intense rainfall during prolonged rainstorms for hazard assessment and warning.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Forestry
Adam G. Wells, Todd J. Hawbaker, J. Kevin Hiers, Jason Kean, Rachel A. Loehman, Paul F. Steblein
Summary: This study aimed to predict burn severity using pre-fire conditions and estimate the potential post-fire debris flow to unburned areas. Fuels, pre-fire weather, and topography were important predictors of burn severity. Predicted burn severity can be used to predict fire effects and identify potential hazards for prioritizing response and mitigation.
INTERNATIONAL JOURNAL OF WILDLAND FIRE
(2023)
