Burn Severity Maps - 2017 and 2018 Wildfires

The following maps indicate burn severity levels of the 2017 and 2018 wildfires on the Willamette National Forest.

A burn severity map is generated using satellite imagery and validated and adjusted by field surveys.

High burn severity is evidenced by the consumption of all ground cover and surface organic matter (litter, duff, fine roots), sometimes leaving a layer of ash several inches deep. Moderate burn severity areas will have up to 80 percent ground cover consumed however, soil structure is generally unchanged. In areas with low burn severity, the ground often appears lightly charred.

The higher the burn severity, the less likely soil is able to absorb rainfall, increasing surface runoff and risk of erosion, debris flows, and flooding.

Using the burn severity maps, scientists calculate expected increases in stream flows and run models that identify areas prone to erosion or landslides. If there are values at risk such as public safety, roads, buildings, recreation sites, trails, historic and cultural sites, and more, we focus on protecting those areas first.