Investigators concluded today that a pesky 1,400-acre wildfire--still burning along the eastern side of Skyline Drive--was started by people.

Whether the fire was set intentionally or resulted from carelessness was not clear, investigators said. But the blaze, which began Tuesday and was mostly under control this afternoon, was not sparked by natural causes, according to park spokeswoman Lyn Rothgeb.

"Most fires like this during this time of year are from lightning strikes, and there was no lightning in the area when this fire started," Rothgeb said. "It could be carelessness, it could be a camp fire, a cigarette tossed into leaves, or it could be arson."

State fire officials have determined that arson caused an 850-acre fire that began Monday in Page County and is now under control. Two other fires--one that burned nearly 1,000 acres near Roanoke and another that consumed 250 acres in Shenandoah County--are under scrutiny. Both are contained, though the Shenandoah County fire flared briefly this afternoon.

Although winds dropped today, high winds earlier this week and continued dry conditions helped the flames spread among the fallen leaves, brush and mountain laurel on the forest floor, officials said. Rainfall in the Virginia mountains has been about 75 percent below normal.

"With these four large fires at one time and the high wind conditions, our resources have been stretched so thin," said David Coffman, a spokesman for the Virginia Department of Forestry. "We've sort of done that checker-board game of bringing all the people we could get from the eastern part of the state to the western part."

Here in the park, state firefighters have gotten help from dozens of others from as far away as Idaho.

Jack Haddox, a firefighter who flew in last night from the Targhee National Forest in eastern Idaho, said much of the fire was burning at or near ground level, with flames rising a foot high through the low-lying brush. Haddox, who was out inspecting the fire for most of the day after arriving at the park at midnight Wednesday, described the blaze as "low intensity."

"It's mild down there," said Haddox, who was called in as part of an interagency fire management team after park resources were depleted. "But the conditions are still quite dangerous, as there is very thick brush and it's fairly steep and rocky. It's very hard to move through a lot of it."

Haddox said firefighters spent much of today clearing trenches along the outer edges of the fire, scraping vegetation from a swath of land, then burning brush back toward the fire. The process is designed to starve the fire of fuel and impede its progress.

Smoke from the low flames billowed from the mountain, and a hazy layer hugged Skyline Drive.

Part of the fire extended into the adjoining Rapidan Wildlife Management Area, which is open to hunting and has several access points, including a fire road and several trails.

Rothgeb said a four- to five-mile stretch of the Appalachian Trail would likely remain closed through at least Friday as firefighters work to contain the fire. She said she expects the fire to be fully contained by Friday evening. Crews backed out of the area about 6 p.m. today, letting the fire "rest" overnight as temperatures were slated to drop and humidity was expected to rise.

Low winds and clear skies are expected to help firefighters on Friday. About 80 firefighters arrived here today as part of a national team, and about 100 additional firefighters from across the region were scheduled to arrive this afternoon and into Friday.

CAPTION: Amber Hodges, a Shenandoah National Park firefighter and information officer, inspects smoldering stump near Bootens Gap.