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Jason Kean

My research focuses on the processes controlling debris-flow initiation and growth, particularly after wildfire, but also in unburned areas.

This research includes a field component that obtains direct measurements of debris flows in natural settings, a modeling component that seeks to explain the observations, and an applied component that focuses on assessment of debris-flow hazards. My previous research at the USGS focused on river mechanics, including bank erosion and the development of model-based approaches to gage streams and rivers.

Education and Certifications

  • University of Colorado, Ph.D., 2003, Civil Engineering

    University of Colorado, M.S., 1998, Civil Engineering

    Cornell University, B.S., 1994, Civil Engineering

Science and Products

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USGS science for a changing world logo

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 standardized approa
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Community for Data Integration (CDI)
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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 standardized approa
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person standing on step slope with debris flow deposits and burned trees in background

January 2021: Evaluation of debris flow activity in recent California Burn Areas following atomospheric river event

The January 2021 atmospheric river event produced heavy rainfall in some areas burned by wildfires in 2020. The Landslide Hazards Program (LHP) staff has evaluated the debris-flow activity in several areas. The locations are: The Carmel Fire, the CZU Lightning Complex Fire (San Mateo and Santa Cruz), the Dolan Fire, and the River Fire burn areas.Reports by date are below. Photos will be posted...
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Natural Hazards, Landslide Hazards
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January 2021: Evaluation of debris flow activity in recent California Burn Areas following atomospheric river event

The January 2021 atmospheric river event produced heavy rainfall in some areas burned by wildfires in 2020. The Landslide Hazards Program (LHP) staff has evaluated the debris-flow activity in several areas. The locations are: The Carmel Fire, the CZU Lightning Complex Fire (San Mateo and Santa Cruz), the Dolan Fire, and the River Fire burn areas.Reports by date are below. Photos will be posted...
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mud, large boulders, and overturned FTE next to house

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...
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Natural Hazards, Landslide Hazards
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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...
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Topographic map of post-fire debris flow

Emergency Assessment of Post-Fire Debris-Flow Hazards

Estimates of the probability and volume of debris flows that may be produced by a storm in a recently burned area, using a model with characteristics related to basin shape, burn severity, soil properties, and rainfall. Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS...
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center
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Emergency Assessment of Post-Fire Debris-Flow Hazards

Estimates of the probability and volume of debris flows that may be produced by a storm in a recently burned area, using a model with characteristics related to basin shape, burn severity, soil properties, and rainfall. Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS...
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View of monitoring basin from the debris-flow fan near Chaffee County Road 162.

Chalk Cliffs, Colorado

Chalk Cliffs, located 8 miles southwest of Buena Vista, CO, is one of the most active debris-flow areas in the state.
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center
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Chalk Cliffs, Colorado

Chalk Cliffs, located 8 miles southwest of Buena Vista, CO, is one of the most active debris-flow areas in the state.
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Bluebird Canyon landslide, near Laguna Beach CA

Rainfall and Landslides in Southern California

A summary of recent and past landslides and debris flows caused by rainfall in Southern California.
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center
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Rainfall and Landslides in Southern California

A summary of recent and past landslides and debris flows caused by rainfall in Southern California.
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Debris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2015

Chalk Cliffs, located 8 miles southwest of Buena Vista, Colorado, is one of the most active debris-flow areas in the state (U.S. Geological Survey). Three stations were set up at Chalk Cliffs which are located sequentially along a channel draining the 0.3 km2 study area. These stations are equipped with rain gauges, laser distance meters, and data loggers to record rainfall and stage data (Kean, e
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Geologic Hazards Science Center

Debris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2016

Chalk Cliffs located 8 miles southwest of Buena Vista, Colorado, is one of the most active debris-flow areas in the state (U.S. Geological Survey). Three stations were set up at Chalk Cliffs which are located sequentially along a channel draining the 0.3 km2 study area. These stations are equipped with rain gauges, laser distance meters, and data loggers to record rainfall and stage data (Kean, et
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Geologic Hazards Science Center

Data supporting an analysis of the recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States

This data release supports the analysis of the recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States. We define the recurrence interval of the peak 15-, 30-, and 60-minute rainfall intensities for 316 observations of post-fire debris-flow occurrence in 18 burn areas, 5 U.S. states, and 7 climate types. These data support the analysis described in Staley
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Landslide Hazards

Debris-flow monitoring data, Chalk Cliffs, Colorado, USA, 2014

This data release includes 2014 time-series data from three debris-flow monitoring stations at Chalk Cliffs in Chaffee County, Colorado, USA. The data were collected to help identify the triggering conditions, magnitude, and mobility of debris flows at the site. The three stations are located sequentially along a channel draining the 0.3 km^2 study area. The Upper, Middle, and Lower stations have
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Landslide Hazards, Geologic Hazards Science Center

Post-wildfire debris-flow monitoring data, Las Lomas, 2016 Fish Fire, Los Angeles County, California, November 2016 to February 2017

This data release includes time-series data from a monitoring site located in a small (0.12 km2) drainage basin in the Las Lomas watershed in Los Angeles County, CA, USA. The site was established after the 2016 Fish Fire and recorded a series debris flows in the first winter after the fire. The station is located along the channel at the outlet of the study area (34 9'18.50"N, 117 56'41.3
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Landslide Hazards

Debris-flow inundation and damage data from the 9 January 2018 Montecito Debris-Flow Event

On 9 January 2018, intense rain above Montecito, California triggered a series of debris flows from steep catchments in the Santa Ynez Mountains. These catchments were burned three weeks earlier by the 1140 km2 Thomas Fire. After exiting the mountain front, the debris flows traveled over 3 km down a series of alluvial fans, killing 23 people and damaging over 400 homes. To understand the flow dyna
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Landslide Hazards

Map and model input and output data covering N 40.0 40.375 and W 105.25 105.625 in the northern Colorado Front Range for analysis of debris flow initiation resulting from the storm of September 9 13, 2013

Rainfall on 913 September 2013 triggered at least 1,138 debris flows in a 3430 km2 area of the Colorado Front Range. Most flows were triggered in response to two intense rainfall periods, one 12.5-hour-long period on 1112 September, and one 8-hour-long period on 12 September. Data in this project pertain to an area bounded by N 40.0 40.375 and W 105.25 105.625 which includes many of the areas wh
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Landslide Hazards
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Multi-model comparison of computed debris flow runout for the 9 January 2018 Montecito, California post-wildfire event

Hazard assessment for post-wildfire debris flows, which are common in the steep terrain of the western United States, has focused on the susceptibility of upstream basins to generate debris flows. However, reducing public exposure to this hazard also requires an assessment of hazards in downstream areas that might be inundated during debris flow runout. Debris flow runout models are widely availab
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Natural Hazards, Volcano Hazards, Geologic Hazards Science Center, Volcano Science Center

Movement of sediment through a burned landscape: Sediment volume observations and model comparisons in the San Gabriel Mountains, California, USA

Post-wildfire changes to hydrologic and geomorphic systems can lead to widespread sediment redistribution. Understanding how sediment moves through a watershed is crucial for assessing hazards, developing debris flow inundation models, engineering sediment retention solutions, and quantifying the role that disturbances play in landscape evolution. In this study, we used terrestrial and airborne li
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Postwildfire soil‐hydraulic recovery and the persistence of debris flow hazards

Deadly and destructive debris flows often follow wildfire, but understanding of changes in the hazard potential with time since fire is poor. We develop a simulation‐based framework to quantify changes in the hydrologic triggering conditions for debris flows as postwildfire infiltration properties evolve through time. Our approach produces time‐varying rainfall intensity‐duration thresholds for ru
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Natural Hazards, Geologic Hazards Science Center

U.S. Geological Survey wildland fire science strategic plan, 2021–26

The U.S. Geological Survey (USGS) Wildland Fire Science Strategic Plan defines critical, core fire science capabilities for understanding fire-related and fire-responsive earth system processes and patterns, and informing management decision making. Developed by USGS fire scientists and executive leadership, and informed by conversations with external stakeholders, the Strategic Plan is aligned wi
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Ecosystems, Natural Hazards, Earth Resources Observation and Science Center, Science Analytics and Synthesis (SAS), Alaska Science Center, Earth Resources Observation and Science (EROS) Center , Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Geologic Hazards Science Center, Geology, Geophysics, and Geochemistry Science Center, Western Ecological Research Center (WERC)

Forecasting the frequency and magnitude of postfire debris flows across southern California

Southern California has a long history of damaging debris flows after wildfire. Despite recurrent loss, forecasts of the frequency and magnitude of postfire debris flows are not available for the region like they are for earthquakes. Instead, debris flow hazards are typically assessed in a reactive manner after wildfires. Such assessments are crucial for evaluating debris flow risk by postfire eme
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

Time since burning and rainfall characteristics impact post-fire debris flow initiation and magnitude

The extreme heat from wildfire alters soil properties and incinerates vegetation, leading to changes in infiltration capacity, ground cover, soil erodibility, and rainfall interception. These changes promote elevated rates of runoff and sediment transport that increase the likelihood of runoff-generated debris flows. Debris flows are most common in the year immediately following wildfire, but temp
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Natural Hazards, Geologic Hazards Science Center

Progress and lessons learned from responses to landslide disasters

Landslides have the incredible power to transform landscapes and also, tragically, to cause disastrous societal impacts. Whereas the mechanics and effects of many landslide disasters have been analyzed in detail, the means by which landslide experts respond to these events has garnered much less attention. Herein, we evaluate nine landslide response case histories conducted by the U.S. Geological
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Natural Hazards, Geologic Hazards Science Center, Geology, Minerals, Energy, and Geophysics Science Center

Measuring basal force fluctuations of debris flows using seismic recordings and empirical green's functions

We present a novel method for measuring the fluctuating basal normal and shear stresses of debris flows by using along‐channel seismic recordings. Our method couples a simple parameterization of a debris flow as a seismic source with direct measurements of seismic path effects using empirical Green's functions generated with a force hammer. We test this method using two large‐scale (8 and 10 m3) e
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

The recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States

In the southwestern United States, post-fire debris flows commonly initiate during short bursts of intense rainfall. To date, the frequency of the rainfall rates has not been quantified. Here, we combine an existing database of debris-flow occurrences and corresponding peak storm intensities with a geospatial library of rainfall recurrence interval (RI) information and climate type to determine th
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Natural Hazards, Geologic Hazards Science Center

Landslides after wildfire: Initiation, magnitude, and mobility

In the semiarid Southwestern USA, wildfires are commonly followed by runoff-generated debris flows because wildfires remove vegetation and ground cover, which reduces soil infiltration capacity and increases soil erodibility. At a study site in Southern California, we initially observed runoff-generated debris flows in the first year following fire. However, at the same site three years after the
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center

The impact of sediment supply on the initiation and magnitude of runoff-generated debris flows

Rainfall intensity‐duration (ID) thresholds are commonly used to assess the potential for runoff‐generated debris flows, but the sensitivity of these thresholds to sediment supply, which can change rapidly with time, is relatively unexplored. Furthermore, debris flows often self‐organize into distinct surges, but the factors controlling the magnitude and frequency of these surges, including sedime
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Natural Hazards, Geologic Hazards Science Center

The influence of frost weathering on the debris flow sediment supply in an alpine basin

Rocky, alpine mountains are prone to mass wasting from debris flows. The Chalk Cliffs study area (central Colorado, USA) produces debris flows annually. These debris flows are triggered when overland flow driven by intense summer convective storms mobilizes large volumes of sediment within the channel network. Understanding the debris flow hazard in this, and similar alpine settings, requires
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Natural Hazards, Landslide Hazards, Geologic Hazards Science Center
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Post-wildfire Landslides Becoming More Frequent in Southern California

Southern California can now expect to see post-wildfire landslides occurring almost every year, with major events expected roughly every ten years, a...

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