The Twitchell Canyon fire, a lightning-caused blaze burning in Utah, has consumed more than 40,000 acres since it began on July 20, 2010. As of Sept. 29 when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft captured this image, the fire was making its way down the mountain slope towards Interstate 15, about 5 miles east of Sulphurdale. Firefighters were using aerial and ground ignition in front of the fire to contain the blaze. In this simulated natural color image, the actively burning areas are shown in red, based on information from ASTER's thermal infrared channels. The image covers an area of 21.5 by 34.7 miles (34.7 by 49.3 kilometers), and is located at 38.4 degrees north latitude and 112.5 degrees west longitude.

With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington, D.C.

More information about ASTER is available at http://asterweb.jpl.nasa.gov/.