A wildfire near Bakersfield, California, burned through 2,600 acres on Monday and prompted the evacuation of 500 homes near Sequoia National Park, according to NBC News. More than $4 million has been spent battling the massive blaze since it ignited last week, the site reported.

The Kern County Fire Department said the cause of the so-called Shirley Fire is still under investigation, NBC News reported.

According to NBC News and Reuters, more than 1,000 firefighters have been containing the the fire, which ignited Friday night on the park's outskirts northeast of Bakersfield. Tom Efird, a battalion chief with the Garden Valley Fire Protection District, noted that "we've had a tremendous amount of air assets that have helped us hold this fire in check." Two houses were lost in the blaze and one was damaged, but “we don’t see that number going up,” Efird added.

According to the U.S Forest Service, flames fueled by high winds and dry brush jumped containment lines on Saturday, despite the efforts of water-dropping helicopters and aircraft.  No injuries have been reported from the fire.

According to Reuters, the nose gear of an air tanker aiding in the fire-fighting efforts collapsed on returning to Fresno Airport on Sunday evening, damaging the aircraft yet leaving its two crew members unhurt.

California’s fire season has been quite severe in 2014, as one of the most severe droughts in the Golden State's history has played a key role in the amount and size of wildfires.

Since Jan. 1, Cal Fire has responded to more than 1,500 wildfires -- nearly double its five-year average over the same period.

The fire department has hired additional seasonal firefighters and bolstered fire equipment earlier in the season, according to reports.