(Text modified to highlight the work of Innovate staff. Story courtesy the USGS EROS Around the Center Article.)
When a wildfire rages across the landscape, the danger seldom ends with a fading ember. Danger often lurks after a fire dies as rain unleashes a muddy slurry of water, soil, vegetation, and boulders down steep slopes.
Post-fire response teams rely on Landsat imagery and the associated remote-sensing products derived, in part, at USGS EROS near Sioux Falls, SD, for the projections that help response teams prepare for the worst.
Innovate staff such as Claudia Young, Stephen Palka, Jacob Casey, and Roger Sneve help to produce a Differenced Normalized Burn Ratio (dNBR) index shortly after a wildfire ends. The index relies on pre- and post-fire Landsat images of the burned area to capture a range of values signifying either an uptick or decrease in greenness across the fire’s footprint. The more negative the values, the more greenness. The greater the magnitude of the positive values, you can interpret that as the more severely the fire impacted the surface cover.
Those values are then categorized into four loosely defined classes: unburned, low-burn severity, moderate severity, and high severity. That information is transformed into Burned Area Reflectance Classification (BARC) data that are provided to Burned Area Emergency Response (BAER) teams to use in the field as a guide for more in-depth field measurements and observations of fire damage.
As quickly as possible, the BAER teams turn all that information into Soil Burn Severity Maps, which are used to stabilize landscapes where needed and hopefully prevent further damage to life, communities, property, or natural resources.
Burn maps to support BAER teams are actually produced by both EROS and the USDA Forest Service’s Geospatial Technology and Applications Center (GTAC). GTAC burn maps cover primarily Forest Service and Department of Agriculture lands. EROS takes care of the Department of Interior-managed lands.
That’s important for several reasons. Hillside soils, vegetation, and rocks no longer anchored by forested mountainsides can pose erosion and runoff risks to water quality in the area. That in turn can impact fish and other habitat. To help prevent that, post-fire mitigation efforts often include quickly reseeding, or putting up barriers to redirect future mud and debris flows.
What Innovate staff are trying to accomplish is about more than making dNBR indices and BARC maps. It’s about savings lives, about protecting communities and natural resources, long after the last ember has cooled. With Innovate’s help, with GTAC and the Landslide Hazards Program and all the work of the BAER and Watershed Emergency Response Teams (WERT), it appears they are succeeding at that.