More than 1,700 wildfires are burning across the state of California, where dry, windy conditions continue to make it difficult for firefighters to put out the flames. According to the California Department of Forestry and Fire Protection, a total of 667,863 acres have been burned since June 20, destroying 81 homes while threatening more than 13,000. The costs are estimated to be greater than $200 million.

The United States Forest Service and the National Interagency Fire Center continue to tap all their resources to help contain the fires. In particular, they have called on, once again, NASA to use its unmanned aerial vehicle, Ikhana, equipped with a new thermal-imaging sensor to track the fires. The 12-channel spectral sensor is more sensitive in the thermal range and can track fires with greater accuracy than can current methods to map fires, such as using line scanners. The data from the new sensor is automatically processed onboard the aircraft and then sent to ground stations, where it is incorporated into a Google Earth map.

The data is displayed in an array of colors to let firefighters know where the fire is actively burning, as well as identify areas that are cooling. This helps the firefighters determine where to deploy resources.

Ikhana conducted its first operational mission on July 8; it mapped fires such as the American River Complex, Piute, Clover, Northern Mountain, and BTU Lightning Complex. "The technology is performing flawlessly," says Everett Hinkley, the National Remote Sensing Program's manager at the U.S. Forest Service and a principal investigator on the project to test and develop the sensor. "We are getting updates to the California fire folks within 30 minutes. Never have they had updates this fast. The key ingredient is having satellite communications to be able to push images to a server as they are acquired."

Hinkley has provided Technology Review with exclusive images (see below) taken during yesterday's mission. Use the legend as a guide: the fire's hot, active spots are yellow; warm areas that were recently burned are shades of red; and areas that are cooling are blue.

The American River Complex fire is located in Foresthill, in Placer County.

The Piute fire, located in Twin Oaks, in the South Sierra Wilderness, has burned 33,152 acres and is 28 percent containe

Another view of the Piute fire.

Images credit: NASA