Hundreds of acres of woodlands were burning yesterday in separate fires along the mountainous backbone of western Virginia that stretched the state's resources and required out-of-state help, officials said.

A blaze just north of Roanoke involved about 900 acres, and before firefighters contained it yesterday afternoon, it had threatened subdivisions near Salem, officials said. Tankers filled with water were stationed in some neighborhoods as a precaution.

A 1,300-acre fire still burned in Madison and Greene counties yesterday afternoon, much of it within the borders of Shenandoah National Park, just east of Skyline Drive. Parts of the Appalachian Trail and several smaller trails were closed, and authorities said they were watching the fire, with an eye to closing the drive if necessary.

Lou Southard, Virginia Department of Forestry state fire chief, said high winds, low humidity and 18 months of drought in the western part of the state have contributed to the duration and frequency of the fires, which by late yesterday had caused no serious injury or property damage.

Tuesday night, the Shenandoah park fire created a red glow on the mountainsides that could be seen for miles, and yesterday there were reports of smoke visible 30 miles away. Near the blaze, the smell of burning wood filled the air.

"There is a complete layer of smoke coming from right above [where we live]," said Rodney Lillard, 36, who lives about five miles from the fire. "I see lots of smoke. It's extremely hazy." But he and other neighbors said they were not too worried, because the blaze burned in an isolated area far from any houses.

Fire crews were still patrolling two other fires in the western part of the state that began earlier in the week but had been contained by yesterday--one in Page County, just south of the community of Stanley, and the other in Shenandoah County, south and east of Woodstock, along Interstate 81. John Margraf, a National Weather Service meteorologist, said winds that have gusted up to 30 mph and have encouraged the fires in recent days are expected to subside by the end of the week. But no precipitation is expected.

Authorities do not know how this week's fires started. Southard said the response to the four blazes has required hundreds of firefighters--more than usually are needed in the fall.

"We've been moving people from the eastern part of the state to the western part of the state," Southard said. He said eastern Virginia has been less vulnerable to fire because it got more rainfall from hurricanes this summer and fall.

The fire north of Roanoke was reported Monday night and was thought to have been contained by late Tuesday, said Dana Perry, a spokeswoman for the Roanoke County Fire and Rescue Department. But the blaze jumped a fire line and spread into a mountainous area of ravines and gullies before it was controlled late yesterday.

Some of the 100 state and local firefighters working there reported minor injuries, such as ankle sprains and minor burns, Perry said.

Lyn Rothgeb, spokeswoman for Shenandoah National Park, said the fire there was reported Tuesday shortly after noon. Park officials have closed the Appalachian Trail for four miles near Bear Fence Mountain.

Rothgeb said 100 firefighters from various federal agencies were flying into Dulles International Airport early this morning and were expected at the fire by dawn today.

The fire in Page County burned about 600 acres, and the fire in Shenandoah County burned about 250 acres, Southard said.

Closer to home, Prince George's County firefighters were busy yesterday afternoon fighting a rash of brush fires in the Mitchellville, Upper Marlboro and Bowie areas.

Staff writer Eugene Meyer contributed to this report.

CAPTION: Charlene Frankavitz and children Ben, 4, and Danielle, 8, watch a fire set by firefighters behind their Roanoke County home to stop the progress of the forest fire.