Objective definition of rainfall intensity–duration thresholds for the initiation of post-fire debris flows in southern California

Landslides ◽  
2012 ◽  
Vol 10 (5) ◽  
pp. 547-562 ◽  
Author(s):  
Dennis M. Staley ◽  
Jason W. Kean ◽  
Susan H. Cannon ◽  
Kevin M. Schmidt ◽  
Jayme L. Laber
Keyword(s):  
Debris Flows ◽  
Southern California ◽  
Rainfall Intensity ◽  
Fire Debris ◽  
Definition Of

scholarly journals Brief communication: Meteorological and climatological conditions associated with the 9 January 2018 post-fire debris flows in Montecito and Carpinteria, California, USA

2018 ◽  
Vol 18 (11) ◽  
pp. 3037-3043 ◽  
Author(s):  
Nina S. Oakley ◽  
Forest Cannon ◽  
Robert Munroe ◽  
Jeremy T. Lancaster ◽  
David Gomberg ◽  
...  
Keyword(s):  
High Intensity ◽  
Debris Flows ◽  
Southern California ◽  
Cold Front ◽  
Santa Barbara ◽  
Fire Debris ◽  
Orographic Enhancement

Abstract. The Thomas Fire burned 114 078 ha in Santa Barbara and Ventura counties, southern California, during December 2017–January 2018. On 9 January 2018, high-intensity rainfall occurred over the Thomas Fire burn area in the mountains above the communities of Montecito and Carpinteria, initiating multiple devastating debris flows. The highest rainfall intensities occurred with the passage of a narrow rainband along a cold front oriented north to south. Orographic enhancement associated with moist southerly flow immediately ahead of the cold front also played a role. We provide an explanation of the meteorological characteristics of the event and place it in historic context.

scholarly journals Synoptic conditions associated with cool season post-fire debris flows in the Transverse Ranges of southern California

2017 ◽  
Vol 88 (1) ◽  
pp. 327-354 ◽  
Author(s):  
Nina S. Oakley ◽  
Jeremy T. Lancaster ◽  
Michael L. Kaplan ◽  
F. Martin Ralph
Keyword(s):  
Debris Flows ◽  
Southern California ◽  
Cool Season ◽  
Transverse Ranges ◽  
Synoptic Conditions ◽  
Fire Debris

scholarly journals Brief Communication: Meteorological and climatological conditions associated with the 9 January 2018 post-fire debris flows in Montecito and Carpinteria California, USA

2018 ◽  
Author(s):  
Nina S. Oakley ◽  
Forest Cannon ◽  
Robert Munroe ◽  
Jeremy T. Lancaster ◽  
David Gomberg ◽  
...  
Keyword(s):  
High Intensity ◽  
Debris Flows ◽  
Southern California ◽  
Cold Front ◽  
Santa Barbara ◽  
Fire Debris ◽  
Orographic Enhancement

Abstract. The Thomas Fire burned 114,078 hectares in Santa Barbara and Ventura Counties, southern California, during December 2017–January 2018. On 9 January 2018, high intensity rainfall occurred over the Thomas Fire burn area in the mountains above the communities of Montecito and Carpinteria, initiating multiple devastating debris flows. The highest rainfall intensities occurred with the passage of a narrow rainband along a north-to-south oriented cold front. Orographic enhancement associated with moist southerly flow immediately ahead of the cold front also played a role. We provide an explanation of the meteorological characteristics of the event and place it in historic context.

RAINFALL INTENSITY-DURATION THRESHOLDS FOR POST-WILDFIRE DEBRIS FLOWS IN ARIZONA

2018 ◽  
Author(s):  
Carissa A. Raymond ◽  
◽  
Luke McGuire ◽  
Ann M. Youberg
Keyword(s):  
Debris Flows ◽  
Rainfall Intensity

Observations and Analyses of the 9 January 2018 Debris-Flow Disaster, Santa Barbara County, California

2021 ◽  
Vol 27 (1) ◽  
pp. 3-27
Author(s):  
Jeremy T. Lancaster ◽  
Brian J. Swanson ◽  
Stefani G. Lukashov ◽  
Nina S. Oakley ◽  
Jacob B. Lee ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Extreme Rainfall ◽  
Atmospheric Conditions ◽  
Santa Barbara ◽  
Debris Removal ◽  
Fire Debris ◽  
Santa Barbara County ◽  
Coastal Land

ABSTRACT The post–Thomas Fire debris flows of 9 January 2018 killed 23 people, damaged 558 structures, and caused severe damage to infrastructure in Montecito and Carpinteria, CA. U.S. Highway 101 was closed for 13 days, significantly impacting transportation and commerce in the region. A narrow cold frontal rain band generated extreme rainfall rates within the western burn area, triggering runoff-driven debris flows that inundated 5.6 km2 of coastal land in eastern Santa Barbara County. Collectively, this series of debris flows is comparable in magnitude to the largest documented post-fire debris flows in the state and cost over a billion dollars in debris removal and damages to homes and infrastructure. This study summarizes observations and analyses on the extent and magnitude of inundation areas, debris-flow velocity and volume, and sources of debris-flow material on the south flank of the Santa Ynez Mountains. Additionally, we describe the atmospheric conditions that generated intense rainfall and use precipitation data to compare debris-flow source areas with spatially associated peak 15 minute rainfall amounts. We then couple the physical characterization of the event with a compilation of debris-flow damages to summarize economic impacts.

scholarly journals Landslides after wildfire: initiation, magnitude, and mobility

Landslides ◽  
2020 ◽  
Vol 17 (11) ◽  
pp. 2631-2641
Author(s):  
Francis K. Rengers ◽  
Luke A. McGuire ◽  
Nina S. Oakley ◽  
Jason W. Kean ◽  
Dennis M. Staley ◽  
...  
Keyword(s):  
Debris Flows ◽  
Rainfall Intensity ◽  
Ground Cover ◽  
First Year ◽  
Mass Wasting ◽  
Soil Infiltration ◽  
Infiltration Capacity ◽  
The Past ◽  
Long Duration ◽  
Southwestern Usa

Abstract 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 fire, the mass-wasting response to a long-duration rainstorm with high rainfall intensity peaks was shallow landsliding rather than runoff-generated debris flows. Moreover, the same storm caused landslides on unburned hillslopes as well as on slopes burned 5 years prior to the storm and areas burned by successive wildfires, 10 years and 3 years before the rainstorm. The landslide density was the highest on the hillslopes that had burned 3 years beforehand, and the hillslopes burned 5 years prior to the storm had low landslide densities, similar to unburned areas. We also found that reburning (i.e., two wildfires within the past 10 years) had little influence on landslide density. Our results indicate that landscape susceptibility to shallow landslides might return to that of unburned conditions after as little as 5 years of vegetation recovery. Moreover, most of the landslide activity was on steep, equatorial-facing slopes that receive higher solar radiation and had slower rates of vegetation regrowth, which further implicates vegetation as a controlling factor on post-fire landslide susceptibility. Finally, the total volume of sediment mobilized by the year 3 landslides was much smaller than the year 1 runoff-generated debris flows, and the landslides were orders of magnitude less mobile than the runoff-generated debris flows.

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