Dennis M. Staley Jason W. Kean Jaime Kostelnik Jonathan M. King Eric S. Jones Robert G. Schmitt Francis K. Rengers Matthew A. Thomas Jacquelyn Negri 20260127 vector digital data https://doi.org/10.5066/P142R8E2 Wildfire can substantially alter the hydrologic response of watersheds to rainfall, and debris-flow activity is among the most destructive consequences of these events. To assist federal, state, and local agencies in planning for postfire hazards, the U.S. Geological Survey (USGS) conducts debris-flow hazard assessments for recent wildfires. This page holds all postfire debris-flow hazard assessments produced by the USGS during 2022. Each hazard assessment is provided as an attached zip archive. The zip archives follow the naming convention <fire>_<start date>_<id>.zip, where <fire> is the name of the fire event, <start date> is the date the fire started, and <id> is the fire ID used by legacy distribution tools. Each assessment maps the modeled likelihood, potential volume, and combined hazard of debris flows across the burn area for a series of design rainstorms. Each assessment also include estimates of the rainfall rates required to trigger debris flows. These results are generally representative of the conditions immediately after the fire. Assessment results are provided as Shapefiles, and each assessment includes one or more README files documenting the provided Shapefiles and relevant data fields. All assessments include a README named "PostFireDFEstimates_README.pdf", which describes fields that report hazard modeling results for various design storms. Some assessments also include a README named "PostFireDFThresholdEstimates_README.pdf", which describes fields that report the rainfall thresholds needed to trigger debris flows for various design probability levels. Each assessment also includes a pdf image named "image.pdf" that maps the combined hazard results for a selected design rainstorm. Although the README files are mostly accurate, they have several known issues. First, many assessment datasets include files and/or data fields not described in their associated READMEs. These extra fields are processing artifacts of the hazard modeling algorithm, so do not represent relevant results. Second, all fields described by the READMEs have been truncated to 10 characters in the data tables. Third, all README fields that begin with "M1_X" instead begin with "L_X" in the data tables. Fourth, the field named "M1_R" in the READMEs is named "R" in the data tables. Assessments were produced by USGS personnel running legacy codebases designed to implement: * The "M1" debris-flow likelihood model of Staley and others (2017) * The "emergency" potential sediment volume model of Gartner and others (2014) * The debris-flow combined hazard classification scheme of Cannon and others (2010) Operational personnel may have modified stream network delineation and modeling parameters in order to ensure quality. References: Cannon, S.H., Gartner, J.E., Rupert, M.G., Michael, J.A., Rea, A.H., and Parrett, C., 2010, Predicting the probability and volume of postwildfire debris flows in the intermountain western United States: Geological Society of America Bulletin, v. 122, no. 1-2, p. 127-144, https://doi.org/10.1130/B26459.1. Gartner, J.E., Cannon, S.H., and Santi, P.M., 2014, Empirical models for predicting volumes of sediment deposited by debris flows and sediment-laden floods in the transverse ranges of southern California: Engineering Geology, v. 176, p. 45-56, https://doi.org/10.1016/j.enggeo.2014.04.008. Staley, D.M., Negri, J.A., Kean, J.W., Laber, J.L., Tillery, A.C., and Youberg, A.M., 2017, Prediction of spatially explicit rainfall intensity–duration thresholds for post-fire debris-flow generation in the western United States: Geomorphology, v. 278, p. 149-162, https://doi.org/10.1016/j.geomorph.2016.10.019. These assessments were produced in response to elevated debris-flow hazards following wildfire events, and were intended to assist federal, state, and local agencies in planning for postfire hazards. 20220121 20220910 ground condition Complete None planned -123.6000 -104.9800 48.9800 31.9200 ISO 19115 Topic Category geoscientificInformation USGS information products data release USGS Thesaurus landslides hazards fires maps and atlases landslide susceptibility assessment hazard preparedness mathematical modeling USGS Metadata Identifier USGS:68bb4323d4be025329aa1c18 Common geographic areas United States North America No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons Zero v1.0 Universal (CC0-1.0) public domain dedication and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. U.S. Geological Survey, Landslide Hazards Program GHSC Data Steward GHSC Data Steward mailing and physical

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Golden CO 80401 US 3032738500 ghsc_metadata@usgs.gov BAER, GTAC, and EROS supported the collection of input datasets used to implement the hazard models. Assessments were reviewed by USGS personnel prior to publication. Personnel may have modified stream network delineation and modeling parameters in order to ensure quality. No formal logical tests were performed. This collection represents all postfire debris-flow hazard assessments released by the U.S. Geological Survey Landslide Hazards Program during 2022. Provided by collaborators at BAER, GTAC, and/or EROS 20130101 vector digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info perimeter Used to define the burn area USGS National Map 1/3rd arc-second DEM 20130101 raster digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info dem Used to compute flow pathways, slopes, and vertical relief. Provided by collaborators at BAER, GTAC, and/or EROS 20130101 raster digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info dnbr Used to inform debris-flow likelihood models. Provided by collaborators at BAER, GTAC, and/or EROS 20130101 raster digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info severity Informs network delineation, debris-flow likelihood models, and volume models. STATSGO KFFACT 19950901 vector digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info kf Used to inform debris-flow likelihood models. LANDFIRE 20160101 raster digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info evt Informs network delineation. Los Angeles County 20130101 vector digital data Digital and/or Hardcopy 20130101 20231231 See Supplemental Info retainments Informs network delineation. Assessments were produced by USGS personnel running legacy codebases designed to implement: * The "M1" debris-flow likelihood model of Staley and others (2017) * The "emergency" potential sediment volume model of Gartner and others (2014) * The debris-flow combined hazard classification scheme of Cannon and others (2010) Operational personnel may have modified stream network delineation and modeling parameters in order to ensure quality. References: Cannon, S. H., Gartner, J. E., Rupert, M. G., Michael, J. A., Rea, A. H., and Parrett, C. (2010). Predicting the probability and volume of postwildfire debris flows in the intermountain western United States. Bulletin, 122(1-2), 127-144. Gartner, J. E., Cannon, S. H., and Santi, P. M. (2014). Empirical models for predicting volumes of sediment deposited by debris flows and sediment-laden floods in the transverse ranges of southern California. Engineering Geology, 176, 45-56. Staley, D. M., Negri, J. A., Kean, J. W., Laber, J. L., Tillery, A. C., and Youberg, A. M. (2017). Prediction of spatially explicit rainfall intensity–duration thresholds for post-fire debris-flow generation in the western United States. Geomorphology, 278, 149-162. perimeter dem dnbr severity kf evt retainments 20220121 Dennis M Staley USGS - ALASKA REGION Research Physical Scientist mailing and physical

Glenn Olds Hall Alaska Pacific University, Alaska Pacific Univ.Grace Hall

Anchorage AK 99508 907-786-7423 dstaley@usgs.gov Vector String PostFireDFEstimates_README.pdf Documents shapefiles and relevant data fields holding debris-flow likelihood, potential sediment volume, and combined hazard results Producer Defined PostFireDFThresholdEstimates_README.pdf Documents shapefiles and relevant data fields holding rainfall threshold results. Producer Defined xxxYYYY_ThresholdGuidance_Basin.txt Table of median rainfall threshold values for the xxxYYYY fire as calculated over the catchment basins. Producer Defined xxxYYYY_ThresholdGuidance_Segment.txt Table of median rainfall threshold values for the xxxYYYY fire as calculated over the stream segments. Producer Defined image.pdf Static map illustrating combined hazard modeling results for a selected design storm. Producer Defined xxxYYYY_analysis_extent_feat.shp Holds the bounding box of the analysis domain for the xxxYYYY fire. Producer Defined xxxYYYY_Basin_DFPredictions_DDmin_IImmh.shp Catchment basin hazard modeling results for the xxxYYYY fire modeled for a design storm with a peak DD minute rainfall intensity of II millimeters per hour. Producer Defined xxxYYYY_Basin_RainfallEstimates_DDmin_RainAtP_PP.shp Catchment basin rainfall estimates for the xxxYYYY fire over a DD minute interval for a probability level of PP percent. Producer Defined xxxYYYY_basinpt_feat.shp Holds the catchment basin outlet points for the xxxYYYY fire. Producer Defined xxxYYYY_centroid_feat.shp Holds the centroid of the fire perimeter for the xxxYYYY fire. Producer Defined xxxYYYY_perim_feat.shp Holds the fire perimeter for the xxxYYYY fire. Producer Defined xxxYYYY_Segment_DFPredictions_DDmin_IImmh.shp Stream segment hazard modeling results for the xxxYYYY fire modeled for a design storm with a peak DD minute rainfall intensity of II millimeters per hour. Producer Defined xxxYYYY_Segment_RainfallEstimates_DDmin_RainAtP_PP.shp Stream segment rainfall estimates for the xxxYYYY fire over a DD minute interval for a probability level of PP percent. Producer Defined xxxYYYY_watchstream_feat.shp Holds the locations of watchstreams for the xxxYYYY fire. Producer Defined U.S. Geological Survey - ScienceBase mailing address

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P142R8E2 None 20260127 Jonathan King U.S. Geological Survey, Landslide Hazards Program Research Physical Scientist mailing and physical

1711 Illinois St

Golden CO 80401 US 3032738500 jking@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998