Wildfire
Wildfire is an unplanned and unwanted fire burning in a natural area. Wildfires can spread to developed lands and pose a severe risk to life and property. UrbanFootprint ingests publicly available wildfire risk datasets and intersects them with the threatened people and property.
The U.S. has seen many billion-dollar wildfire disasters. Wildfires such as Lahaina, Marshall, and Paradise have wiped out entire communities and caused unprecedented losses of life and property. Disasters like these may become more common due to factors such as global warming and the expansion of development into the wildland-urban interface.
To better assess, plan and adapt to these conditions, UrbanFootprint Wildfire provides the annual probability of wildfire in current and future scenarios.
UrbanFootprint addresses organizations' need to capture the risk of wildfire by geospatially intersecting the best available models of wildfire risk (Wildfire Risk to Communities datasets) with the people and property that are threatened. The models that generate this data consider wildfire risk from fires that ignite in wildlands and then spread to urban areas. The modeled spread of wildfire is limited to 1,530 meters (~1 mile) from the perimeter of urban areas. The model authors note that this limit is consistent with observed structural losses in urban areas due to wildfires over the last 20 years. Therefore, urban areas more than 1 mile from the boundary are not considered to be at risk of wildfire.
For current wildfire probability, we use Wildfire Risk to Communities, a high-resolution (30 x 30 m), vetted national fire risk dataset with several layers that provide a variety of wildfire severity metrics. Specifically, we use the following layers:
Burn probability (BP) layer provides the annual probability of wildfire (at any flame length greater than 0 feet) burning at the location.
Flame length exceedance probability layers of 4 feet and 8 feet (FLEP4 and FLEP8) – indicate the conditional probability of flame length exceeding 4 feet and 8 feet if a wildfire occurs. Greater flame lengths generally indicate greater wildfire intensity.
Using the burn probability and flame length exceedance probabilities, we calculate the probability of wildfire with flames exceeding 4 feet and 8 feet:
Probability of wildfire with flames exceeding 4 ft = BP (burn probability) x FLEP4 (flame length exceedance probability 4 ft)
Probability of wildfire with flames exceeding 8 ft = BP (burn probability) x FLEP8 (flame length exceedance probability 8 ft)
For future wildfire probability, we follow the emerging scientific consensus (Gao, et al. (2021), Gutierrez, et al. (2021), Riley, et al. (2016)) that identifies high temperatures as a strong predictor of future burn probabilities. Specifically, to estimate the future burn probability, we scale the current probabilities based on the forecasted number of days above 95°F, where 95°F is the threshold above which wildfire burn probability increases substantially.
Availability: Location Insights | Climate & Hazard Insights | Energy Program Insights