Tracking Wildfires With Weather Radars

Abstract

There is a need for nowcasting tools to provide timely and accurate updates on the location and rate of spread (ROS) of large wildfires, especially those impacting communities in the wildland urban interface. In this study, we demonstrate how fixed‐site weather radars can be used to fill this gap. Specifically, we develop and test a radar‐based fire‐perimeter tracking tool that leverages the tendency for local maxima in the radar reflectivity to be collocated with active fire perimeters. Reflectivity maxima are located using search radials from points inside a fire polygon, and perimeters are updated at intervals of ∼10 min. The algorithm is tested using publicly available Next Generation Weather Radar radar data for two large and destructive wildfires, the Camp and Bear Fires, both occurring in northern California, USA. The radar‐based fire perimeters are compared with available, albeit limited, satellite and airborne infrared observations, showing good agreement with conventional fire‐tracking tools. The radar data also provide insights into fire ROS, revealing the importance of long‐range spotting in generating ROS that exceeds conventional estimates. One limitation of this study is that high‐resolution fire perimeter validation data are sparsely available, precluding detailed error quantification for the radar estimates drawn from samples spanning a range of environmental conditions and radar configurations. Nevertheless, the radar tracking approach provides the basis for improved situational awareness during high‐impact fires.

Fire in the Earth System: Introduction to the Special Collection

“…Recent examples in this Special Collection include the work of Yanagiya and Furuya (2020), who used L-band ALOS2 data and C-band InSAR data from Sentinel-1 to map thermokarst from postfire permafrost thaw in Siberia, and Loría-Salazar et al (2021), whose MODIS and VIIRS data were compared against ground-based observations, allowing them to summarize the scope, limitations, and opportunities for new applications of surface-level aerosol concentrations generated from wildfires. Lareau et al (2022) showed the utility of Next Generation Weather Radar data for tracking wildfires, as fire perimeters estimated using radar were found to be consistent with satellite infrared measurements. Airborne radar measurements of a pyrocumulonimbus cloud by Rodriguez et al (2020) were the first of their kind.…”

“…Lareau et al. (2022) showed the utility of Next Generation Weather Radar data for tracking wildfires, as fire perimeters estimated using radar were found to be consistent with satellite infrared measurements. Airborne radar measurements of a pyrocumulonimbus cloud by Rodriguez et al.…”

“…Lareau et al. (2022) discussed the importance of long‐range spotting in driving the rate of fire spread, inferred from new applications of weather radar data. Katurji et al.…”

“…Studying extreme pyroconvective behavior of the 2016 Pioneer megafire (Idaho, USA) using airborne radar and in situ aircraft sampling, Rodriguez et al (2020) presented data that help explain how hot-moist updrafts trigger fire-generated thunderstorms (from pyrocumulonimbus clouds) that pose aviation hazards. Lareau et al (2022) discussed the importance of long-range spotting in driving the rate of fire spread, inferred from new applications of weather radar data. Katurji et al (2021) presented novel field measurements using turbulent thermal image velocimetry at the immediate fire-atmosphere interface, showing interactions between the flame zone and wind turbulence.…”

Toward a Better Understanding of Wildfire Behavior in the Wildland-Urban Interface: A Case Study of the 2021 Marshall Fire

“…First, while the most up-to-date version of WRF-Fire as of this writing (version 4.4) contains a firebrand parameterization, it does not ignite spot fires, but rather provides only a likelihood of spot fire ignition. Rapid wildfire spread is often caused by embers generating new ignitions ahead of the main fire front (e.g., N. P. Lareau et al, 2022). The Marshall Fire was able to cross Highway-36, which is a six-lane interstate.…”