Though the first day of fall arrives on September 22, the Yukon Flats National Wildlife Refuge in interior Alaska had already begun to transition into autumn orange and brown on September 15, 2010, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this image. Three fires, marked with red, burn in the low hills around the river, masking the landscape with billowing smoke.
Fire is essential in maintaining a healthy ecosystem in the lowlands around the Yukon River. Fire burns through the mixed conifer and hardwood forests, creating a checkerboard of habitats made up of trees of varying ages and types. Some of this variability is visible in the image, though soil, light, and water availability also influence the type of forest that grows in a particular location. Patches dark green spruce forest is mixed with brown shrub lands, and orange deciduous forest of aspen and white birch.
The Yukon Flats are among the most fire-prone landscapes in Alaska. Fire season typically falls between April and July, when lightning strikes are frequent. Naturally-ignited fires are typically permitted to burn in the Yukon Flats National Wildlife Refuge unless they pose a threat to communities, historic sites, or other high-value resources.
NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.
