Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2021-11-02 Title: Soil Burn Severity Dataset for the SCHNEIDER SPRINGS Fire occurring on the Okanogan/Wenatchee 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: SCHNEIDER SPRINGS Agency: USDA Forest Service Type of assessment: Emergency Fire size (as mapped): 113697 acres Pre-Fire Imagery Date : 2020-08-30 Post-Fire Imagery Date : 2021-09-24 Output Dataset Projection: LUnits_meters Datum: D_North_American_1983 Spheroid Name: GRS_1980 Mapping Comments: None Product List SCHNEIDER SPRINGS_sbs.tif = Soil burn severity (SBS) dataset in raster format SCHNEIDER SPRINGS_SBS thumb.jpg = JPEG version of the SBS Time Period of Content Multiple Dates/Times Single Date/Time Calendar Date: 2020-08-30 (pre-fire image) Single Date/Time Calendar Date: 2021-09-24 (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: 501553.393022 East Bounding Coordinate: 530473.393022 North Bounding Coordinate: 1435010.97777 South Bounding Coordinate: 1405590.97777 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: WA Place Keyword: SCHNEIDER SPRINGS 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 Original BARC thresholds: Unburned/Low threshold = 67 Low/Moderate threshold = 132 Moderate/High threshold = 226 Revised SBS thresholds: Unburned/Low threshold = 67 Low/Moderate threshold = 119 Moderate/High threshold = 164 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. Additionnal comments: The September 24th BARC image provided by GTAC was field verified. Soil data points were collected following methodology outlined in Field Guide for Mapping Post-Fire Soil Burn Severity RMRS-GTR-243. Stratified sampling was conducted in all burn severity classes to verify burn severity and identify thresholds between classes. Survey123 was used to collect data. Soil data points were color-classified by burn severity class and adjustments were made to BARC thresholds to reflect burn severity observed in the field. The September 20th BARC image was used to fill in cloud-masked areas within the September 24th image (approx. 200 acres). Reclassification was made to the BARC thresholds as follows: Unburned <= 67; Low > 67 and <= 119; Moderate > 119 and <= 194; and High > 194. Where September 20th BARC was absent to fill in unclassified pixels in the September 24th BARC (area around the edges in the north - approx. 55 acres), these pixels were classified as Low Severity. Field reconnaissance indicated that areas with prior timber management activities showed a higher severity on the ground than was shown in the BARC image. Specifically, specialists noted areas of moderate soil burn severity where tree canopy remained intact and viable (green). Because the canopy remained intact, the BARC imagery had classified these areas as low due to the lack of canopy mortality. The open canopy, reduced ladder fuels in the area, and post management activities resulted in a high survival rate for the large trees. However, soil conditions indicate fire intensity and/or residency time at the surface was significant. Because of these inconsistencies, areas with management activities within the past 10 years were extracted and validated separately to capture the actual on the ground soil conditions and better predict the watershed response. The Timber Harvest feature class from EDW (Enterprise Data Warehouse) showing awarded harvest areas within the past 10 years was used to extract these areas for separate adjustment. Reclassification was made to the thresholds for these harvest areas as follows: Unburned <=52; Low >52 and <= 89; Moderate > 89 and <=164; and High > 164. This reclassified raster was mosaicked with the overall reclassification raster, replacing the original values with those from the reclassified timber harvest raster. Two majority filter passes were then made to clean up single pixel differences. Rock Outcrops, Talus and Rubble Land were mapped within the fire perimeter using 1-m resolution Lidar and aerial imagery. This layer was then converted from a polygon to a raster format with the same resolution as the BARC imagery (20m). Gridcode 5 was assigned to Rock Outcrops and gridcode 6 to Talus/Rubble Land. This raster was mosaicked with the reclassified burn severity raster, replacing the burn severity values with the rock/talus/rubble-land cover values. This allows for more accurate modeling and analysis. 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: LUnits_meters Map Projection Parameters Standard Parallel: 43.0 Standard Parallel: 48.0 Longitude of Central Meridian: -120.0 Latitude of Projection Origin: 34.0 False Easting: 600000.0 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: 2021-11-02 Metadata Contact Contact Information Contact Organization Primary Contact Organization: USDA Forest Service, Geospatial Technology and Applications Center (GTAC) Contact Person: Craig Baker 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 3763 Contact Electronic Mail Address: baerimagery@fs.fed.us