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Day-by-day comparisonThese images, taken from July 9 through July 17, show the development of a major wildfire that ripped through Stanislaus County, Calif.
At 7 p.m. on July 9, there is only a small yellow spot, indicating that a fire had burned in the area at some point during the calendar year. By 3 a.m. the next morning, however, several red spots appear, indicating active fires. The fires continue to grow over the next few days, peaking on July 12. The last image shown here, taken by the MODIS instruments at 7 a.m. on July 17, shows how extensive the burn area was.
An update on the Forest Service's Web site the evening of July 17 indicated the fire was approximately 85 percent contained but had scorched nearly 33,000 acres of land.
Several government sites make it possible to get frequently updated information on active wildfires. The National Interagency Fire Center has updated news and information regarding the status of active wildfires, as well as statistics on past fires and suppression costs.
NASA satelliteNASA uses the MODIS Rapid Response System as part of its SensorWeb project, in which sensors circling the earth act in a network, detecting fires or other events. When a MODIS sensor sees a fire, it alerts other sensors with the fire's location so they can collect additional information in the area.
Steve Chien, of NASA's Jet Propulsion Laboratory, explains how the networked satellites work in this short video.