Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2024-11-20 Title: Soil Burn Severity Dataset for the pack trail Fire occurring on the Bridger-Teton 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 Landsat 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. 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: pack trail Agency: USDA Forest Service Type of assessment: Emergency Fire size (as mapped): 92534 acres Pre-Fire Imagery Date (Fish Creek fire mapping #1) : 2023-09-25 Pre-Fire Imagery Date (Fish Creek fire mapping #2) : 2024-08-11 Pre-Fire Imagery Date (Pack Trail fire mapping #1) : 2022-10-16 Pre-Fire Imagery Date (Pack Trail fire mapping #2) : 2022-10-16 Post-Fire Imagery Date (Fish Creek fire mapping #1) : 2024-09-20 Post-Fire Imagery Date (Fish Creek fire mapping #2) : 2024-08-27 Post-Fire Imagery Date (Pack Trail fire mapping #1) : 2024-10-14 Post-Fire Imagery Date (Pack Trail fire mapping #2) : 2024-10-21 Output Dataset Projection: NAD_1983_UTM_Zone_12N Datum: D_North_American_1983 Spheroid Name: GRS_1980 Mapping Comments: None Product List pack_trail_wy4359411014720240915_sbs.tif = Soil burn severity (SBS) dataset in raster format pack_trail_wy4359411014720240915_SBS.png = PNG thumbnail version of the SBS Time Period of Content Multiple Dates/Times Single Date/Time Calendar Date: 2023-09-25 (pre-fire image - Fish Creek fire mapping #1) Calendar Date: 2024-08-11 (pre-fire image - Fish Creek fire mapping #2) Calendar Date: 2022-10-16 (pre-fire image - Pack Trail fire mapping #1) Calendar Date: 2022-10-16 (pre-fire image - Pack Trail fire mapping #2) Single Date/Time Calendar Date: 2024-09-20 (post-fire image - Fish Creek fire mapping #1) Calendar Date: 2024-08-27 (post-fire image - Fish Creek fire mapping #2) Calendar Date: 2024-10-14 (post-fire image - Pack Trail fire mapping #1) Calendar Date: 2024-10-21 (post-fire image - Pack Trail fire mapping #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: 561249.0845130896 East Bounding Coordinate: 586209.0845130896 North Bounding Coordinate: 4844662.001006747 South Bounding Coordinate: 4811422.001006747 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: WY Place Keyword: pack trail 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 Landsat 9 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 SBS Metadata (process for creating the SBS): The Fish Creek Fire had a separate BAER assessment completed. After the completion of that assessment, the two fires merged and were from then on known as the Pack Trail Fire. This added to the complexity of creating a final soil burn severity dataset for the full Pack Trail fire area. For the Fish Creek portion of the fire and due to clouds, active fire, and smoke over the fire area in all available post-fire images, two BARC mappings were completed and combined using the best available data from each BARC image to derive the final SBS for the Fish Creek fire area. The BARC image was used in conjunction with identified critical values and ground access to identify priority areas for field verifying SBS. Field assessment was recorded in Field Maps. Once field assessment was complete, Soil Scientists adjusted BARC raster bins to align with field data. Overall BARC was overestimating burn severity within the Fish Creek Fire. Many areas originally classified as moderate showed low SBS on the ground due to low shrub (sagebrush) and grass cover. These vegetation types are light flashy fuels that don't have a high enough residence time while burning to result in mod/high SBS. In timber, it was determined that there was a lower amount of high SBS than originally mapped in the BARC. While tree canopy was consumed and dead/down logs were charred, root structures were still intact in many areas, with some areas showing new growth post-fire. After bins were adjusted for the 0920 BARC, the same values were used in the 0827 BARC after verifying that it produce similar trends in similar vegetation types. After both BARCs were adjusted, a new polygon layer was created for filling in masked areas. This was done by overlaying those polygons and splitting/reshaping them based on underlaying vegetation and area trends to match BARC layers. The polygons were then rasterized and combined with both BARCs. A majority filter was applied before creating a final SBS for the Fish Creek fire area. Here are the notes on each BARC map for the Pack Trail fire area (excluding the previously mapped areas within the Fish Creek fire area) and how the breaks were made based on field observations (from the air and on the ground). One thing to note is that the BARC from 10/14 and the BARC from 10/21 had very similar breaks, but very different pixel values (meaning one pixel on 10/14 did not necessarily have the same value on 10/21). Because of this it was important to utilize the two different BARCs to make the breaks and finalize the SBS map. BARC Data from 10/14/2024: This BARC was utilized to make changes within the initial fire area (except for the masked areas from 10/14 – explained later). We decreased high slightly and increased low as well based on field observations. Some areas did seem to have sections of higher SBS (Whitebark pine areas), but overall the high was slightly overrepresented. The low was underrepresented in the meadow areas. Original BARC Breaks: Unburned/Very Low: 0 - 72 Low: 73 - 122 Moderate: 123 - 173 High: 174 - 254 Breaks used for SBS: Unburned/Very Low: 0 - 72 Low: 73 - 126 Moderate: 127 - 169 High: 170 – 255 Purdy Burn Scar: BARC from 10/14 utilized with different breaks as seen below. In this area we increased both moderate and low based on aerial observations. Original 10/14 BARC Breaks: Unburned/Very Low: 0 - 72 Low: 73 - 122 Moderate: 123 - 173 High: 173 - 254 SBS Breaks: Unburned/Very Low: 0 - 65 Low: 66 -105 Moderate: 106 - 169 High: 170 - 254 BARC data from 10/21/2024: We utilized the BARC from 10/21 for the additional burned acreage that occurred between 10/14 and 10/21. We reduced the amount of high based on field observations. Although many of the areas had less than 20% cover and no needlecast potential, the soil had fairly intact roots with shallow ash layers present. Original 10/21 BARC Breaks: Unburned/Very Low: 0 - 73 Low: 74 - 121 Moderate: 122 - 171 High: 172 - 254 SBS Breaks: Unburned/Very Low: 0 - 73 Low: 74 - 135 Moderate: 136 - 190 High: 191 – 254 Masked Areas from BARC 10/14: Utilized the BARC 10/21 values to make the SBS breaks for these masked areas as they matched better with the 10/21 BARC. Here we increased the amount of moderate as well as the amount of low. Meadow areas mostly burned at low SBS. Original 10/21 BARC Breaks: Unburned/Very Low: 0 - 73 Low: 74 - 121 Moderate: 122 - 171 High: 172 – 254 New SBS Breaks: Unburned/Very Low: 0 - 73 Low: 74 - 130 Moderate: 131 - 198 High: 199 – 254 After the four different areas were reclassified (as above) the .tifs were the geoprocessing to Mosiac to a New Raster was used to combine the different pieces. This combined raster was then run through the Majority filter to create the final product. Additional Comments: Soil Hydrophobicity: The background hydrophobicity in the mixed conifer and Lodgepole pine stands was moderate. In the High SBS areas and in some of the Moderate SBS areas, the post fire soil hydrophobicity was strong and tended to go down to 4 cm or deeper. Within the meadow areas, background and post fire hydrophobicity were weak. Roots: In some of the areas mapped as high on the BARC, roots were found to be generally intact with only very fine roots being affected, sometimes consumed. Fine roots were generally scorched but only in the top 1 to 2 cm and overall the coarse roots were unaffected. This led to reducing some of the high areas to moderate. Previously/Recently harvested areas: Many of these stands had log decks that burned hot, creating smaller pockets of High soil burn severity which wasn’t really picked up on the BARC Meadow Areas: the Sheridan Creek meadow only had some very small patches of willow that were consumed. Several meadows on the BT side looked to have higher severity from the air. Meadow areas near Buffalo Meadows (for example Park Creek Meadow) had a lot more burned willows with some sage, but overall, the sage didn’t burn except in smaller patches. Where the meadows did burn, it was flashy so the vegetation itself burned hot, but the soils did not. 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: 30.0 Ordinate Resolution: 30.0 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: 2024-11-20 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