Sometimes the destructive nature of wildland fires lies beyond the flames. It reveals itself in what is left behind—scorched mountainsides with no trees to stop rain-driven mudslides or dangerous debris flows. When such potential exists, the Shortwave Infrared (SWIR) bands on the sensors aboard the Landsat satellites help to identify those possibilities quickly.
The SWIR bands measure diminished moisture content in soil and vegetation. When SWIR band 7 is paired with Landsat’s Near-Infrared (NIR) band 5, which is highly sensitive to growing vegetation, the two produce vivid, accurate images of burn scars. That information is useful to post-fire responders who must act quickly to stabilize burn areas and address potential risks to people, property, and communities nearby.
Landsat 8 helped map destruction caused by the Cougar Creek fire 75 miles northeast of Portland, Oregon, in mid-August 2015. At left is a pre-fire image of Mount Adams in Washington. Snow appears cyan on its peak. In the middle is a post-fire image where the previous green vegetation south and east of the mountain is now charred and appears in shades of red. The burn severity map at right was produced with Landsat’s infrared imaging, including a SWIR band that is found on few other satellites. Within the fire perimeter, dark green is non-burned, light blue is low burn severity, yellow is moderate severity, and red is high.