October 16, 2018, marks the two-year anniversary of the Cottonwood Fire in western South Dakota. The fire consumed a large swath of grassland near the community of Wall and just north of Badlands National Park.
Thanks to low relative humidity, and high winds and temperatures, the fire spread quickly. It burned 41,360 acres by the time it was 100 percent contained two days later.
Imagery from Landsat and Sentinel-2 show the fire scar and relatively rapid recovery of the grassland in the two years since the fire. The Sentinel-2A image from October 31, 2016, shows the burn scar just 13 days after the fire was contained.
Recovery of a grassland fire happens more quickly than a forest fire. With enough moisture, grasses in fire-adapted landscapes use the postfire flush of nutrients to rapidly regrow. Only a very faint outline of the burn scar is visible in the 2017 Landsat 8 image. By 2018, the burn scar has disappeared.
Landsat and Sentinel have similar spatial resolutions and infrared imaging capabilities, allowing them to complement each other in burn severity monitoring.