Wildfires spread across a parched West.

Dozens of lightning-sparked wildfires seared the western United States last week, adding hundreds of thousands of acres of charred terrain to a tally that promises to make this fire season the worst in recent decades.

On Aug. 8, at least 66 major fires--which had already burned at least 100 acres each--were raging in 11 western states, say officials at the National Interagency Fire Center (NIFC) in Boise, Idaho. The center, which coordinates wildland firefighting operations, is home to personnel from seven federal agencies, including the Bureau of Land Management, the National Park Service, and the National Weather Service.

In all, the 66 active fires covered more than 865,000 acres, says Mary Stansell, a spokeswoman for the center. So far this year, almost 64,000 major fires have burned in excess of 4.1 million acres. On average during the past decade, about 54,000 fires each year have charred about 2.2 million acres by the second week of August, she notes.

On some occasions, wildfires have yielded an unexpected bonus. When a 23,000-acre blaze called the Bircher fire swept across Mesa Verde National Park in southwestern Colorado in late July, it stripped away vegetation that had hidden more than a hundred ancient cliff dweller sites. Researchers had to scramble to protect the newfound artifacts before fire-fighting activities could damage them. Now, archaeologists accompany each of the firefighting teams in the park, says Gwen Shaffer, NIFC fire information officer at a field site near Mesa Verde.

The Bircher fire was extinguished Aug. 5, but Shaffer says a new fire in the park, dubbed the Pony fire, already has burned more than 5,000 acres. It passed through areas above and below the cliff dwelling known as the Long House. Shaffer says this fire didn't directly threaten the ancient structure because the canyon didn't contain much vegetation. Archaeologists are now concerned that increased erosion resulting from the fires atop the mesa may damage the Long House, she adds.

Dry conditions throughout the western United States contribute to the mounting toll of burned acreage this fire season. "It's unusual for the entire West to be dry all at once," says Melanie Miller, a fire ecologist with the Bureau of Land Management at the Boise center.

She explains that the desert Southwest usually has received rain by this time of year, so firefighters from that region can deploy to other fire-struck areas. "Fire-fighting resources are stretched really thin," she says, noting that many small blazes are expanding into major fires.

Long-term weather forecasts for the West aren't likely to provide peace of mind, says Rick Ochoa, a National Weather Service meteorologist at the center. The service predicts that the Pacific Northwest and northern portions of the Rocky Mountains will be hotter and drier than normal for the next couple of months.

"We haven't even reached the peak of the fire season yet," Ochoa laments. The season, he adds, has another 60 or so days to go.