By Doug Stanglin, USA TODAY

An unmanned drone aircraft is flying over the vast Rim Firenear Yosemite National Park and sending back real-time data tofirefighters on hot spots and movement of the blaze, fire officials say.

The National Guard Predator drone launched Wednesday froman airfield in Southern California and can remain airborne for 22 hoursat a time.

Daniel Berlant, spokesman for California's state fireagency, says the military drone is being used in its biggestfirefighting test to date and has provided commanders with real-timeimages and information on fire activity near and inside Yosemite.

"Because the fire is so large ... we're hoping that new technology will allow us to better deploy our resources,'' Berlant said.

TheU.S. Forest Service said in a statement that the aircraft "willidentify where fire activity is located and how it is moving, includinglocating and identifying spot fires which will improve the ability toprotect life, property, and natural resources."

The Rim Fire hasgrown to 311 square miles in less than two weeks, and officials say itis 32% contained. More than 4,900 firefighters are battling the blaze,aided by retardant-dropping helicopters and tanker airplanes.

Firefightersgot a break with relatively cooler temperatures and moist air thisweek, but hotter weather is forecast, just as the Labor Day weekendbrings increased visitors to wilderness areas and parks around thecountry.

This fire is one of 10 burning around California, withnearly 10,000 firefighters battling them, With more than two months leftin the normal fire season in California, officials are worried aboutmore big fires like this one flaring up.

"This is one of the lastweekends for families to go out camping and recreating before summerends. While conditions remain ripe for fires ... we're trying to urgeeverybody to be extra cautious outdoors,'' he said.

Fire officialsestimate that the Rim Fire can be contained no sooner than Sept. 10 andthat portions will continue to burn beyond that date.

Theremotely piloted drone, which is the size of a small Cessna, has helpedfirefighters by shouldering the burden normally carried out byhelicopters, which must be refueled every two hours.

The MQ-1unmanned aircraft is from the California Air National Guard's 163rdReconnaissance Wing from Riverside and is operating from VictorvilleAirport. It flew over mostly unpopulated areas on its 300-mile flight tothe Rim Fire

''The drone is providing data directly back to theincident commander, allowing him to make quick decisions about whichresources to deploy and where,'' Berlant said.

Officialswere careful to point out the images are being used only to aid in theeffort to contain the fire. Outside the fire area, it will be escortedby a manned aircraft.

In 2009, a NASA Predator equippedwith an infrared imaging sensor helped the U.S. Forest Service assessdamage from a fire in Angeles National Forest. In 2008, a drone capableof detecting hot spots helped firefighters assess movement of a seriesof wildfires stretching from Southern California's Lake Arrowhead to SanDiego.

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