But the tundra was very dry in 2007 and fire-fueling winds kicked up the blaze.

CNN: Next global warming worry: Thawing tundra

The area near an uphill incline is considered a collection point for fuel and ignition sources, and it's possible a piece of debris fell into the tinder-dry brush early Thursday and sparked the fire, Piranio said.

NPR: Cause Of California Wildfire Appears Accidental

The fire, which is fueled by dry brush and trees, was 30% contained Monday -- threatening structures and prompting an unspecified number of evacuations.

CNN: STORY HIGHLIGHTS

Taking away the thinned-out material is difficult, and sloppy thinning can increase the risk of fire by leaving dry branches and leaves on the forest floor.

ECONOMIST: The fires return