Jonathan M. King Jaime Kostelnik Jason W. Kean 20241119 vector digital data https://doi.org/10.5066/P13GTMAX 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 collection holds all postfire debris-flow hazard assessments produced by the USGS in 2024. Each child item holds the results for a specific hazard assessment. 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 includes estimates of the rainfall rates required to trigger debris flows. These results are generally representative of the conditions immediately after the fire. The results are provided as raw model outputs, so the number of digits following a decimal point does not represent the number of significant figures. The hazard assessments were 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) and the assessments were produced by USGS personnel running the beta version of the ocelote package. Operational personnel may have also modified stream network delineation and modeling parameters for individual assessments in order to ensure quality. The beta version is represented by the ocelote commits prior to the v1.0.0 release. These commits can be found in the ocelote source repository: https://code.usgs.gov/ghsc/lhp/ocelote 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, 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. 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. 20240516 20241209 ground condition Complete None planned -148.9300 -105.0400 63.7600 33.2800 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:68c325ebd4be0260db1940bf 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 in 2024. Provided by collaborators at BAER, GTAC, and/or EROS 20240516 vector digital data Digital and/or Hardcopy 20240516 publication date perimeter Used to define the burn area USGS National Map 1/3rd arc-second DEM 20240516 raster digital data Digital and/or Hardcopy 20240516 publication date dem Used to compute flow pathways, slopes, and vertical relief. Provided by collaborators at BAER, GTAC, and/or EROS 20240516 raster digital data Digital and/or Hardcopy 20240516 publication date dnbr Used to inform debris-flow likelihood models. Provided by collaborators at BAER, GTAC, and/or EROS 20240516 raster digital data Digital and/or Hardcopy 20240516 publication date severity Informs network delineation, debris-flow likelihood models, and volume models. STATSGO KFFACT 20240516 vector digital data Digital and/or Hardcopy 20240516 publication date kf Used to inform debris-flow likelihood models. LANDFIRE 20240516 raster digital data Digital and/or Hardcopy 20240516 publication date evt Informs network delineation. Los Angeles County 20240516 vector digital data Digital and/or Hardcopy 20240516 publication date retainments Informs network delineation. The hazard assessments were 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) and the assessments were produced by USGS personnel running the beta version of the ocelote package. Operational personnel may have also modified stream network delineation and modeling parameters for individual assessments in order to ensure quality. The beta version is represented by the ocelote commits prior to the v1.0.0 release. These commits can be found in the ocelote source repository: https://code.usgs.gov/ghsc/lhp/ocelote 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, 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 20240516 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 0.0197754793 0.0235836429 Decimal seconds North_American_Datum_1983 GRS 1980 6378137.0 298.257222101 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/P13GTMAX None 20251119 U.S. Geological Survey, Landslide Hazards Program GHSC Data Steward GHSC Data Steward mailing and physical

1711 Illinois St

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