Spatial datasets of probabilistic wildfire risk components for the sagebrush biome (270m)

Regional data depicting burn probability (BP) and conditional flame-length probability (FLP) were generated for the sagebrush biome in the western United States using a geospatial Fire Simulation (FSim) system developed by the USDA Forest Service, Missoula Fire Sciences Laboratory. The FSim system includes modules for weather generation, wildfire occurrence, fire growth, and fire suppression. FSim is designed to simulate the occurrence and growth of wildfires under tens of thousands of hypothetical contemporary fire seasons in order to estimate the probability of a given area (i.e., pixel) burning under current (ca. 2020) landscape conditions and fire management practices. The data presented here represent modeled BP and conditional flame-length probability for the sagebrush biome at a 270-meter grid spatial resolution. Flame-length probability is estimated for six standard flame-length classes as follows: FLP1 = < 2 feet (ft); FLP2 = 2 < 4 ft; FLP3 = 4 < 6 ft; FLP4 = 6 < 8 ft; FLP5 = 8 < 12 ft; FLP6 = 12+ ft. Because they indicate conditional probabilities (i.e., representing the likelihood of burning at a certain intensity level, given that a fire occurs), the FLP data must be used in conjunction with the BP data for risk assessment.
In the western United States, hundreds of thousands of acres of highly imperiled sagebrush ecosystems are lost or degraded each year as a result of altered wildfire regimes. In response to these wildfire threats, extensive fuel treatment investments have been proposed throughout the region. Regional-scale assessment of wildfire risk offers a consistent means of evaluating threats to valued resources and assets, thereby facilitating the most cost-effective investments in management activities that can mitigate those risks. We used a simulation system to estimate the probabilistic components of wildfire risk across the sagebrush biome, which includes portions of 13 western states.
These data were produced using methods described herein and used to produce the 3rd edition BP and FLP for national analyses (Dillon et al. 2023), However, where they overlap, this product differs from the national product suite, because this effort used a landscape dataset depicting ca. 2020 fuel conditions that was customized to better reflect expected fire behavior in the sagebrush biome, including influences from exotic annual grass invasion (e.g., cheatgrass) and conifer (e.g., pinyon, juniper) encroachment (Short et al. 2024). These data were published on 12/21/2023. On 03/13/2024, metadata updates included: 1) the correction of the buffer size around each pyrome (was originally stated as 60 kilometers, but has been corrected to 30 kilometers); and 2) the addition of the Joint Fire Science Program Final Report associated with these data.