Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2024-11-19 Title: Soil Burn Severity Dataset for the line Fire occurring on the San Bernadino National Forest Publication Information Publication Place: Salt Lake City, Utah, USA Publisher: USDA Forest Service Geospatial Data Presentation Form: raster digital data Online Linkage: https://fsapps.nwcg.gov/afm/baer/download.php Description Abstract: This soil burn severity dataset was derived from both Landsat and Sentinel 2 data and field validated by a Forest Service Burned Area Emergency Response (BAER) team. It is based upon an initial Burned Area Reflectance Classification (BARC) dataset created by analyzing satellite imagery. A pre-fire and post-fire Landsat scene were processed to develop a differenced Normalized Burn Ratio (dNBR) image for phase 1. A pre-fire and post-fire Sentinel 2 scene were processed to develop a differenced Normalized Burn Ratio (dNBR) image for phase 2. The dNBR image attempts to portray the variation of burn severity within a fire and captures the combined effects of the fire to vegetation and soil components of the ecosytem. The preliminary BARC dataset was assessed by a Forest Service BAER team and modified, if necessary, based on field conditions. Purpose: These data were created by the USDA Forest Service Geospatial Technology and Applications Center (GTAC) to support Burned Area Emergency Response (BAER) teams. Supplemental Information Fire Name: line Agency: USDA Forest Service Type of assessment: Emergency Fire size (as mapped): 44121 acres Pre-Fire Imagery Date Phase 1 : 2024-08-24 Pre-Fire Imagery Date Phase 2 : 2023-10-10 Post-Fire Imagery Date Phase 1 : 2024-09-17 Post-Fire Imagery Date Phase 2 : 2024-10-09 Output Dataset Projection: NAD_1983_UTM_Zone_11N Datum: D_North_American_1983 Spheroid Name: GRS_1980 Mapping Comments: None Product List line_ca3412111715520240906_sbs.tif = Soil burn severity (SBS) dataset in raster format line_ca3412111715520240906_SBS.png = PNG thumbnail version of the SBS Line_BAER_SBS_Phases_Final.shp = Shapefile of phase 1 and phase 2 areas Line_BAER_AssessmentArea_Final.shp = Shapefile of final BAER assessment area Time Period of Content Multiple Dates/Times Single Date/Time Calendar Date: 2024-08-24 (pre-fire image phase 1) Calendar Date: 2023-10-10 (pre-fire image phase 2) Single Date/Time Calendar Date: 2024-09-17 (post-fire image phase 1) Calendar Date: 2024-10-09 (post-fire image phase 2) Currentness Reference: Severity data correspond to the date of the post-fire image. Status Progress: Evaluation of methods in process Maintenance and Update Frequency: As needed Spatial Domain Bounding Coordinates West Bounding Coordinate: 482933.23369645706 East Bounding Coordinate: 505553.23369645706 North Bounding Coordinate: 3786308.2103375825 South Bounding Coordinate: 3772328.2103375825 Keywords Theme Theme Keyword Thesaurus: none Theme Keyword: Wildland Fire Theme Keyword: Wildfire Theme Keyword: Burned Area Emergency Response Theme Keyword: BAER Theme Keyword: dNBR Theme Keyword: Fire Severity Theme Keyword: Burn Severity Theme Keyword: USDA Forest Service Place Place Keyword Thesaurus: none Place Keyword: CA Place Keyword: line Fire Access Constraints: These data are publicly available. Use Constraints: There are no restrictions on use, except for reasonable and proper acknowledgement of information sources and limitations as preliminary/draft data. Data Set Credit: USDA Forest Service Native Data Set Environment: GeoTiff Data Quality Information Positional Accuracy Horizontal Positional Accuracy Horizontal Positional Accuracy Report: Landsat data are terrain corrected using ground control points and processed to an RMSE of less than 1/2 pixel. Lineage Process Step Process Description: These data products are derived from Sentinel 2 data. Pre-fire and post-fire scenes are analyzed to create a differenced Normalized Burn Ratio (dNBR) image. The dNBR image portrays the variation of burn severity within the fire. The pre- and post-fire images are terrain corrected and further processed to convert top of atmosphere reflectance. The Normalized Burn Ratio (NBR) is computed for the pre- and post-fire images using the following formula: (NIR Band - SWIR Band) / (NIR Band + SWIR Band) = NBR The Differenced NBR is computed to determine severity by subtracting the post-fire NBR from the pre-fire NBR: (PreNBR - PostNBR) = dNBR The Line fire BAER assessment and SBS validation was split into 2 phases. Phase 1 was 39,234 acres, and Phase 2 was 4,898 acres mostly on the eastern side of the fire. The field validation and creation of SBS was done separately for each phase, and combined into a single, merged SBS during Phase 2. Field soils data was collected using Parsons et al (2009), soil burn severity mapping using soil mapping fundamentals per Hudson (1992). PHASE 1: A global edit was performed to slightly reduce high soil burn severity to moderate soil burn severity across the entire fire area. A global edit was also performed to slightly increase the amount of moderate soil burn severity from low soil burn severity. Several areas that were previously masked from clouds were updated based on field and aerial photo observations, changing masked areas to moderate SBS. PHASE 2: Only a minor global adjustment was needed in phase 2, changing some low burn severity to moderate. Masked areas were very small in phase 2, so they were not adjusted manually. Additional Comments: Phase 1 Mask areas that were updated manually will be included in the final SBS package, not all masked areas were changed, only the ones that were observed in the field to have soil burn severity different than the BARC. There was an error made in Phase 1 of the SBS creation process that was not caught until after modeling and analysis had been completed for Phase 1. The original resolution of the phase 1 acquisition was 30m. During one of the exports or conversions to the final SBS, the cell size was accidently changed to 20m. This led to pixel averaging, and shifts in the original pixel alignment. This error resulted in the Phase 1 portion of the SBS appearing much more coarse-resolution, almost like a 40m image. While the cell size matches the phase 2 acquisition of 20m, some data and detail was lost during the conversion. Because this cell size error was caught late, after the data was sent to USGS for debris flow modeling, and after it was shared with the California Watershed Emergency Response Team (WERT), the phase 1 SBS was not changed or replaced. This will maintain consistency in the future with the original post-fire analysis that was done using the original burn severity patterns. Original BARC thresholds (Phase 1 area): Unburned/Low threshold = 82 Low/Moderate threshold = 144 Moderate/High threshold = 208 Original BARC thresholds (Phase 2 area): Unburned/Low threshold = 85 Low/Moderate threshold = 142 Moderate/High threshold = 212 Revised SBS thresholds (Phase 1 area): Unburned/Low threshold = 82 Low/Moderate threshold = 135 Moderate/High threshold = 223 Revised SBS thresholds (Phase 2 area): Unburned/Low threshold = 85 Low/Moderate threshold = 137 Moderate/High threshold = 212 General descriptions of the severity classes are below: Unburned / Very low: The area after the fire was indistinguishable from pre-fire conditions. This does not always indicate the area did not burn (i.e. canopy may be occluding the burn signal). Low: Areas of surface fire with little detected change in cover and little detected mortality of the dominant vegetation. Little to no change in the soil color, structure and condition occured. Moderate: This severity class is between low and high and means there is a mixture of detected effects on the dominant vegetation. High: Areas where the canopy has high to complete consumption. Changes to soil structure, color and condition are significant and hydrophobicity may have occured. Spatial Data Organization Information Direct Spatial Reference Method: Raster Raster Object Information Vertical Count: 1 Spatial Reference Information Horizontal Coordinate System Definition Planar Map Projection Map Projection Name: NAD_1983_UTM_Zone_11N Map Projection Parameters Standard Parallel: 0.0 Standard Parallel: 0.0 Longitude of Central Meridian: -117.0 Latitude of Projection Origin: 1.0]];-5120900 -9998100 450445547.391054;-100000 10000;-100000 10000;0.001;0.001;0.001;IsHighPrecisio False Easting: 500000.0 False Northing: 0.0 Planar Coordinate Information Planar Coordinate Encoding Method: row and column Coordinate Representation Abscissa Resolution: 20.0 Ordinate Resolution: 20.0 Planar Distance Units: Meter Geodetic Model Horizontal Datum Name: D_North_American_1983 Ellipsoid Name: GRS_1980 Semi-major Axis: 6378137.0 Denominator of Flattening Ratio: 298.257222101 Distribution Information Resource Description: Downloadable Data Metadata Reference Information Metadata Date: 2024-11-19 Metadata Contact Contact Information Contact Organization Primary Contact Organization: USDA Forest Service, Geospatial Technology and Applications Center (GTAC) Contact Person: Mark Nigrelli Contact Address Address Type: mailing address Address: 125 S. Sate St., Suite 7105 City: Salt Lake City State or Province: UT Postal Code: 84138 Contact Voice Telephone: 801 975 3479 Contact Electronic Mail Address: baerimagery@fs.fed.us