Monitoring Trends in Burn Severity
MTBS consistently maps the location, extent and severity of all large fires occurring in the United States from 1984 to present. Temporally and spatially comprehensive data provided by MTBS supports a variety of policy and resource management information needs.
MTBS selects pre- and post-fire imagery based on types of assessments that vary by landscape/vegetation type. In grasslands and low biomass shrublands initial assessments are performed which utilize post-fire imagery from immediately after the fire to capture burn severity before rapid post-fire changes occur. In forests and high biomass shrublands, extended assessments are performed which utilize post-fire imagery from the following growing season to capture delayed fire effects. Beginning in 2020, MTBS has created initial assessments for all fires greater than 40,000 acres to provide a more rapid data release for large fires. Extended assessments will also be created for these fires during the normal MTBS production cycle.
Developed primarily to monitor the effectiveness of national fire management policies, MTBS data are also is used to assess the immediate and long term effects of fires on the landscape, as a consistently derived source of fire disturbance data used by national land cover and monitoring programs, as a supplemental information tool to inform operational fire suppression decisions by wildfire managers, and provides a rich and unprecedented dataset for analysis and application by the research community.
Burn Severity layers are created by first calculating spectral indices from pre- and post-fire satellite imagery that are sensitive to changes caused by fire. The two images are then subtracted showing the difference between them which is then thresholded into burn severity classes.
- Pre- and post-fire satellite imagery
- Burn area boundary shapefile
- Differenced Normalized Burn Ratio (dNBR) and Relativized dNBR (continuous)
- 6-class thematic thresholded dNBR
- Visualization products