Searchers who have been scouring parts of Great Smoky Mountains National Park in search of a missing backpacker hoped to be aided Saturday by dogs trained to pick up the human scent.

A day-long search Friday, the third day of efforts to find 70-year-old Albert "Morgan" Briggs, failed to turn up any trace of the experienced backpacker who set out a week ago on a four-day trek through the park. Wet weather and rugged conditions have strained rangers, who've had to deal with slippery conditions, hard-to-get-through thickets of rhododendron and mountain laurel, and rock outcrops that require detours.

On Friday, five two-person teams covered a total of nine different drainages and other possible routes between Campsite #31 on the Porters Creek Trail and the Appalachian Trail, but found nothing of significance. Other searchers covered 8 miles of trail from the Appalachian Trail south into North Carolina and out to Newfound Gap Road at Kephart Prong Trailhead.

Rangers hoped Saturday to receive help in their efforts from a search dog organization to get one or more search dogs to be put into the trail areas. Helicopters have not been used so far because of poor weather, and because a dense tree canopy usually makes helicopter use only marginally productive. If weather clears helicopters may be used in future days.

Mr. Briggs is said to be very familiar with the park's backcountry and was one of the park’s first "Appalachian Trail Ridge Runner." Ridge Runners spend several months on the 71 miles of the AT in the park, providing information, performing trail maintenance and serving as the park’s eyes on the trail. He's been described as 5’8, 180 pounds with white hair and balding, a mustache and beard, blue eyes, and often wears glasses. He was reportedly wearing brown Danner hiking boots, a green two-piece rain suit, and blue jeans or khaki slacks.