Fire Aviation USFS EDW RMRS WRC Burn Probability

The data included in this publication depict the 2024 version of components of wildfire risk for all lands in the United States that: 1) are landscape-wide (i.e., measurable at every pixel across the landscape); and 2) represent in situ risk - risk at the location where the adverse effects take place on the landscape. National wildfire hazard datasets of annual burn probability and fire intensity, generated by the USDA Forest Service, Rocky Mountain Research Station and Pyrologix LLC, form the foundation of the Wildfire Risk to Communities data. Vegetation and wildland fuels data from LANDFIRE 2020 (version 2.2.0) were used as input to two different but related geospatial fire simulation systems. Annual burn probability was produced with the USFS geospatial fire simulator (FSim) at a relatively coarse cell size of 270 meters (m). To bring the burn probability raster data down to a finer resolution more useful for assessing hazard and risk to communities, we upsampled them to the native 30 m resolution of the LANDFIRE fuel and vegetation data. In this upsampling process, we also spread values of modeled burn probability into developed areas represented in LANDFIRE fuels data as non-burnable. Burn probability rasters represent landscape conditions as of the end of 2020. Fire intensity characteristics were modeled at 30 m resolution using a process that performs a comprehensive set of FlamMap runs spanning the full range of weather-related characteristics that occur during a fire season and then integrates those runs into a variety of results based on the likelihood of those weather types occurring. Before the fire intensity modeling, the LANDFIRE 2020 data were updated to reflect fuels disturbances occurring in 2021 and 2022. As such, the fire intensity datasets represent landscape conditions as of the end of 2022. Additional methodology documentation is provided in a methods document (\Supplements\WRC_V2_Methods_Landscape-wideRisk.pdf) packaged in the data download. The specific raster datasets in this publication include: Risk to Potential Structures (RPS): A measure that integrates wildfire likelihood and intensity with generalized consequences to a home on every pixel. For every place on the landscape, it poses the hypothetical question, "What would be the relative risk to a house if one existed here?" This allows comparison of wildfire risk in places where homes already exist to places where new construction may be proposed. This dataset is referred to as Risk to Homes in the Wildfire Risk to Communities web application. Conditional Risk to Potential Structures (cRPS): The potential consequences of fire to a home at a given location, if a fire occurs there and if a home were located there. Referred to as Wildfire Consequence in the Wildfire Risk to Communities web application. Exposure Type: Exposure is the spatial coincidence of wildfire likelihood and intensity with communities. This layer delineates where homes are directly exposed to wildfire from adjacent wildland vegetation, indirectly exposed to wildfire from indirect sources such as embers and home-to-home ignition, or not exposed to wildfire due to distance from direct and indirect ignition sources. Burn Probability (BP): The annual probability of wildfire burning in a specific location. Referred to as Wildfire Likelihood in the Wildfire Risk to Communities web application. Conditional Flame Length (CFL): The mean flame length for a fire burning in the direction of maximum spread (headfire) at a given location if a fire were to occur; an average measure of wildfire intensity. Flame Length Exceedance Probability - 4 ft (FLEP4): The conditional probability that flame length at a pixel will exceed 4 feet if a fire occurs; indicates the potential for moderate to high wildfire intensity. Flame Length Exceedance Probability - 8 ft (FLEP8): the conditional probability that flame length at a pixel will exceed 8 feet if a fire occurs; indicates the potential for high wildfire intensity. Wildfire Hazard Potential (WHP): An index that quantifies the relative potential for wildfire that may be difficult to manage, used as a measure to help prioritize where fuel treatments may be needed. Additional methodology documentation is provided with the data publication download. (https://www.fs.usda.gov/rds/archive/Catalog/RDS-2020-0016-2) Note: Pixel values in this image service have been altered from the original raster dataset due to data requirements in web services. The service is intended primarily for data visualization. Relative values and spatial patterns have been largely preserved in the service, but users are encouraged to download the source data for quantitative analysis.本出版物收录的数据为2024版美国全域野火风险（wildfire risk）组分数据集，其满足以下两项判定标准：1） 覆盖全域景观（即可在景观内的每个像素（pixel）点上进行测量）；2） 表征原位风险（in situ risk）——即不良影响发生在景观对应位置处的风险。美国农业部林务局（USDA Forest Service）落基山研究站（Rocky Mountain Research Station）与Pyrologix有限责任公司生成的年度燃烧概率（burn probability）与火灾强度（fire intensity）国家级野火隐患（wildfire hazard）数据集，是《社区野火风险》（Wildfire Risk to Communities）数据集的核心基础数据源。研究采用LANDFIRE 2020（版本2.2.0）的植被与野生地燃料数据作为输入，接入两套独立但关联的地理空间（geospatial）火灾模拟系统。年度燃烧概率通过美国林务局地理空间火灾模拟器（FSim, USFS geospatial fire simulator）生成，初始像元（pixel）分辨率为较粗的270米。为使燃烧概率栅格（raster）数据达到更适用于社区隐患与风险评估的更高分辨率，研究将其上采样至LANDFIRE燃料与植被数据原生的30米分辨率。在本次上采样过程中，研究同时将模拟得到的燃烧概率值赋值至LANDFIRE燃料数据中标记为不可燃的建成区（developed areas）。燃烧概率栅格表征的是2020年末的景观状况。火灾强度特征以30米分辨率开展建模，具体流程为先开展覆盖火灾季全区间天气相关特征的全量FlamMap模拟，再依据各类天气类型的发生概率将模拟结果整合为多类输出成果。在启动火灾强度建模前，研究已对LANDFIRE 2020数据进行更新，以反映2021与2022年发生的燃料扰动（fuels disturbances）事件。因此，火灾强度数据集表征的是2022年末的景观状况。额外的方法文档已随数据下载包一并提供，文档路径为SupplementsWRC_V2_Methods_Landscape-wideRisk.pdf。本出版物收录的具体栅格数据集如下：1. 潜在建筑风险（Risk to Potential Structures, RPS）：整合野火发生可能性、火灾强度与住宅通用损毁后果的评估指标，覆盖每个像元。针对景观内的任意位置，该指标提出假设性问题：“若此处建有住宅，其相对野火风险为多少？”借此可对比已有住宅区域与拟新建住宅区域的野火风险。该数据集在《社区野火风险》网页应用中被称为“住宅野火风险”（Risk to Homes）。2. 潜在建筑条件风险（Conditional Risk to Potential Structures, cRPS）：针对某一特定位置，若发生火灾且该位置建有住宅时，火灾对住宅的潜在损毁后果。该数据集在《社区野火风险》网页应用中被称为“野火损毁后果”（Wildfire Consequence）。3. 暴露类型（Exposure Type）：暴露指野火发生可能性与火灾强度和社区的空间重合度。该图层划分了三类区域：住宅直接受邻近野生植被野火影响的区域、受余烬、住宅间引燃等间接源影响的间接暴露区域，以及因距离直接/间接引燃源过远而无野火暴露风险的区域。4. 燃烧概率（Burn Probability, BP）：特定区域年度内发生野火的概率。该数据集在《社区野火风险》网页应用中被称为“野火发生可能性”（Wildfire Likelihood）。5. 条件火焰长度（Conditional Flame Length, CFL）：若某一位置发生火灾，沿最大蔓延方向（火头）燃烧时的平均火焰长度，是野火强度的平均表征指标。6. 火焰长度超标概率-4英尺（Flame Length Exceedance Probability - 4 ft, FLEP4）：若发生火灾，某像元处火焰长度超过4英尺的条件概率，用于表征野火达到中高强度的可能性。7. 火焰长度超标概率-8英尺（Flame Length Exceedance Probability - 8 ft, FLEP8）：若发生火灾，某像元处火焰长度超过8英尺的条件概率，用于表征野火达到高强度的可能性。8. 野火隐患潜力（Wildfire Hazard Potential, WHP）：用于量化难以管控的野火相对潜在风险的指数，可用于优先确定需要开展燃料处理的区域。额外的方法文档已随数据出版物下载包一并提供，链接为：https://www.fs.usda.gov/rds/archive/Catalog/RDS-2020-0016-2。注意事项：本影像服务中的像元值已根据Web服务的数据要求对原始栅格数据集进行调整。该服务主要用于数据可视化，其相对数值与空间格局基本得以保留，但建议用户下载原始数据源以开展定量分析。