Parking on a pile of dry leaves can be a fire hazard.

Think of it this way: Dry leaves are like dry paper, fire officials say, and can ignite around 400 degrees. A vehicle's undercarriage, even if the vehicle has only been driven a short time, can heat up to about 600 degrees.

"It's a recipe for disaster if that car parks on top of the leaves," said Capt. Tom Polera, a spokesman for the Arlington County Fire Department. "With parking at a premium, people will park anywhere, not realizing what could happen."

On Nov. 11 in Arlington, a 1990 Honda Civic was destroyed after a man parked on a pile of leaves outside his apartment, Polera said. The man had driven only about 10 miles. When he went back outside a short time after parking, Polera said, the car was engulfed in flames.

"In that case, we were able to see almost right away where it started," he said.

No other area jurisdictions have responded to similar incidents this year, although fire officials in Alexandria said they have had problems in the past with hot catalytic converters igniting leaves.

Fire officials in Northern Virginia noted other seasonal dangers as well, including unattended candles and alternative heat sources.

On Nov. 23 in Prince William County, firefighters responded to a house that caught fire because clothing was left near a space heater, said Capt. Tim Taylor, a spokesman for the county's fire and rescue department.

"That's the biggest thing we're seeing here," he said. "We're asking residents who use alternative heat sources to follow the manufacturer's instructions and not to leave them in rooms unattended or near combustibles. With your other heating appliances, be sure that they're serviced and in good working order."

The leaf problem seems especially acute in Arlington, perhaps because the county is home to numerous mature trees, Polera said. In 2004, the county collected about 40,000 cubic yards of leaves, he said, enough to fill the MCI Center basketball court 16 stories high.

Fire officials across the region urged residents to find parking spots free of leaves.

Polera suggested residents collect leaves along streets in front of their homes. Residents should either leave bags for trash haulers to take away or find out whether their jurisdictions have special pickups, he said. In Arlington, for example, the county collects leaves and converts them into mulch.

Officials also urged residents to use caution when decorating for the holidays. Among their advice: Use indoor lights inside only and outdoor lights outside, keep flammable material away from Christmas tree lights, and keep Christmas trees a safe distance from candle flames.