Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2024-10-01 Title: Soil Burn Severity Dataset for the siphon Fire occurring on the Tonto 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 Sentinel 2 scene were processed to develop a differenced Normalized Burn Ratio (dNBR) image. 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: siphon Agency: USDA Forest Service Type of assessment: Emergency Fire size (as mapped): 17059 acres Pre-Fire Imagery Date : 2024-09-10 Post-Fire Imagery Date : 2024-09-15 Output Dataset Projection: NAD_1983_UTM_Zone_12N Datum: D_North_American_1983 Spheroid Name: GRS_1980 Mapping Comments: None Product List siphon_az3343911144120240910_sbs.tif = Soil burn severity (SBS) dataset in raster format siphon_az3343911144120240910_SBS.png = PNG thumbnail version of the SBS Time Period of Content Multiple Dates/Times Single Date/Time Calendar Date: 2024-09-10 (pre-fire image) Single Date/Time Calendar Date: 2024-09-15 (post-fire 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: 450901.0743698043 East Bounding Coordinate: 471341.0743698043 North Bounding Coordinate: 3715431.310734227 South Bounding Coordinate: 3691231.310734227 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: AZ Place Keyword: siphon 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 Completion of the Soil Burn Severity map began with the acquisition of the Burned Area Reflectance Classification (BARC) map layer from Forest Service Geospatial Technology and Applications Center (GTAC). The soil scientist and other team members examined the map in order to determine which areas could be accessed for field verification. Field work took place on September 22 and 23, 2024. The Survey123 data collection app was used on tablets in the burned area to determine actual field conditions. That field data was then uploaded to ESRI’s ArcGIS online. Our GIS specialists then populated that data on to a working copy of the Siphon Fire map. The field data had shown some under-representation of the ‘moderate’ burn severity. Through discussions and by manipulations of the existing BARC data, adjustments were made to the original map, and the final Soil Burn Severity was created. Original BARC thresholds: Unburned/Low threshold = 62 Low/Moderate threshold = 143 Moderate/High threshold = 179 Revised SBS thresholds: Unburned/Low threshold = 62 Low/Moderate threshold = 136 Moderate/High threshold = 179 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: 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: 2024-10-01 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