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PHOTOS: Firefighters Gain Ground on Napa's Wragg Fire

Firefighters are gaining ground on the Wragg fire, which ignited July 22 off Highway 128 near Lake Berryessa, California.

The blaze, which has scorched more than 6,000 acres, was 70 percent contained as of Monday morning, according to Cal Fire.

All evacuation orders have been lifted, following the destruction of two outbuildings. Three other outbuildings and one residence sustained damage.

Despite the progress, firefighters continue to deal with treacherous terrain as the region is brush grass covered, rugged and steep, with difficult access.

In a screen grab from ABC10 Eyewitness News in Sacramento, the station's shows a grass fire is burning vegetation near Lake Berryessa on Wednesday, July 22, 2015. (Photo/ABC10 Sacramento)

The weather is forecast to be mostly sunny and unseasonably hot through Wednesday, with highs in the low and middle 90s F and low relative humidity.

Paired with some afternoon wind each day, this is generally not good news for firefighters, AccuWeather Western Weather Expert Ken Clark said.

"The heat alone will make it extra uncomfortable for the firefighters," he said. "These weather conditions are likely to continue, and get hotter, over the next few days, continuing to fuel the already dry landscape."

While initially reported as a vehicle accident, the cause of the wildfire remains under investigation.

Firefighters Battle Wragg Wildfire in California