Despite the extremely dry conditions in drought-afflicted southern California, the summer's most destructive fires have struck the Northwest and northern California, giving the region the unusual distinction of being the center of this year's wildfire season.

Washington and Oregon account for nearly half of the 2.5 million acres burned by wildfires this year. Over the past decade, only about 7 percent of the total acreage burned per year has been in the Northwest. Meanwhile, the fire-prone Rocky Mountain West and Southwest have been relatively quiet.

This week, the situation in the Northwest could become more dire as unusually hot weather and lightning storms threaten to stoke more fires.

Across the country, 39 large wildfires were burning Wednesday, covering 714,000 acres, according to the National Interagency Fire Center. All but eight are in Washington, Oregon, and California.

Firefighters are trying to subdue a handful of new fires in Washington, while mopping up the remains of the largest wildfire in state history, the Carlton Complex fire. On Monday President Barack Obama declared part of the state a disaster area, authorizing federal assistance to repair damaged public infrastructure. Officials also announced a ban on outdoor burning on state lands.

In eastern Oregon, high winds are making it tricky to corral the 64,000-acre South Fork Complex fire, while in northern California, firefighters continue to battle the 10,700-acre Lodge fire in Mendocino County. Eight firefighters were hurt last Friday when that fire overran them, while at another northern California wildfire on Monday, three firefighters had to deploy emergency shelters to escape that blaze.

View Images In this aerial view of the Carlton Complex fire, the burned areas appear darker brown in comparison to the unburned brushlands and grasslands (tan) and forests (green). The fire is the biggest in Washington state history. Photograph by NASA Earth Observatory

Weather Factors

Nationwide, roughly half the typical acreage has burned. The fire season had promised to be a bad one, with a prolonged drought leaving vegetation tinder-dry across the West. But the circumstances that spark sprawling conflagrations didn't materialize in many places, said Ed Delgado, head of the U.S. Forest Service office that predicts wildfire hazards.

In the Southwest, lightning strikes ignited fires, but then cooler weather helped squelch them. Moist air that sweeps north from Mexico in July arrived on schedule, bringing fire-smothering rains to the Southwest, Nevada, Utah, and parts of Colorado, Delgado said.

"They just didn't have a prolonged period of time that would allow fire to get established and build on itself," he said.

In southern California, the Santa Ana winds that drive wildfires blew briefly in May, but haven't been much of a presence since.

The Northwest wasn't so lucky. Lightning storms in mid-July coincided with a wave of hot, dry weather. A string of fires started, including the Carlton Complex fire in central Washington state, which scorched a record 256,000 acres and more than 400 structures.

Just 55 miles from the center of the Carlton Complex fire, 32 people near the little town of Keller were evacuated from the approaching Devil's Elbow Complex fire. By Tuesday morning it had burned 20,000 acres and threatened 150 homes. It was just 7 percent contained, and the weather forecast wasn't promising. It called for "lots and lots of lightning and some crazy winds," said fire spokesperson Sarah Gracey. "The Northwest has just been crazy this year."

Personnel, Resources Strained

Gracey's presence in Washington testifies to the strain this fire season is putting on the region's firefighters. She works for the state of Kentucky, but was brought in to lend a hand. People from 23 states were involved in the Devil's Elbow Complex fire, from as far away as Florida, she said.

Despite the slower fire season, the Forest Service still predicts that by the end of August, the agency will exceed the $1.3 billion earmarked for firefighting across the U.S.

The state of Washington has already burned through the $19 million budgeted for firefighting there this year, and the season is far from over, said Albert Kassel, head of firefighting for the state's Department of Natural Resources.

The lightning from thunderstorms expected through Wednesday could spark new fires. But the rain and cooler weather could also help dampen them. By the weekend, when warmer, drier weather is predicted, it will be more apparent what challenges firefighters will face in the coming weeks, Delgado said.