Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2024-08-29 Title: Soil Burn Severity Dataset for the horse gulch Fire occurring on the Helena-Lewis and Clark National Forest 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 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 and a pre-fire and post-fire Sentinel 2 were processed to develop a differenced Normalized Burn Ratio (dNBR) image for each timeframe. 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: horse gulch Agency: USDA Forest Service Type of assessment: Emergency Fire size (as mapped): 15183 acres Sentinel-2 Pre-Fire Imagery Date : 2024-06-23 Sentinel-2 Post-Fire Imagery Date : 2024-07-23 Landsat Pre-Fire Imagery Date : 2024-07-08 Landsat Post-Fire Imagery Date : 2024-07-16 Output Dataset Projection: NAD_1983_UTM_Zone_12N Datum: D_North_American_1983 Spheroid Name: GRS_1980 Mapping Comments: None Product List horse_gulch_mt4668911169620240709_sbs.tif = Soil burn severity (SBS) dataset in raster format horse_gulch_mt4668911169620240709_SBS.png = PNG thumbnail version of the SBS Time Period of Content Multiple Dates/Times Single Date/Time Calendar Date: 2024-07-08 (pre-fire Landsat image) Calendar Date: 2024-06-23 (pre-fire Sentinel 2 image) Single Date/Time Calendar Date: 2024-07-16 (post-fire Landsat image) Calendar Date: 2024-07-23 (post-fire Sentinel 2 image) 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: 443232.6822447218 East Bounding Coordinate: 454632.6822447218 North Bounding Coordinate: 5174900.000000006 South Bounding Coordinate: 5166180.000000006 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: MT Place Keyword: horse gulch 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 both Landsat and 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 First aquisition date: HorseGulch_mt4668911169620240709_20240716_utm 1) Adjusting BARC based on field observations of SBS designations 2) Masking VMap grassland polygons the represented broad, convex southing facing slopes as low severity 3) Using aspect to approximate SBS for the 3,000 acres that burned after the intial BARC was aquired Second aquisition date: Horse_Gulch_mt4668911169620240709_20240723_utm 4)Adjusting BARC based on field observations of SBS designations ONLY for the area of growth after the initial BARC (~3,000 acres) 5)Merging first and second SBS products into one First BARC was a Landsat product and second a Sentinel product. The team chose to use the first BARC and SBS for the majority of the fire and not use the Sentinel BARC for the entire fire due to the additional time spent masking and adjusting the original BARC to SBS based on vegetype and landform. Time constraints necessitated using the original BARC to SBS product and making a seperate BARC to SBS product for the ~3,000 acres that were not covered by the initial aquisition rather than creating a new SBS for the entire fire based on the updated sentinel product. Landsat Image 2024/07/16 Original BARC thresholds: Unburned/Low threshold = 71 Low/Moderate threshold = 106 Moderate/High threshold = 160 Revised SBS thresholds: Unburned/Low threshold = 71 Low/Moderate threshold = 104 Moderate/High threshold = 158 Sentinel-2 Image 2024/07/23 Original BARC thresholds: Unburned/Low threshold = 81 Low/Moderate threshold = 106 Moderate/High threshold = 160 Revised SBS thresholds: Unburned/Low threshold = 68 Low/Moderate threshold = 120 Moderate/High threshold = 159 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_12N Map Projection Parameters Standard Parallel: 0.0 Standard Parallel: 0.0 Longitude of Central Meridian: -111.0 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: 10.0 Ordinate Resolution: 10.0 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: 2024-08-29 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