More than four dozen searchers were working at Mount Rainier National Park on Monday to find a 64-year-old hiker who failed to meet up with his son as planned.

The missing hiker, Edwin Birch, of Tacoma, Washington, and his son were hiking the Wonderland Trail in sections, and early Saturday the two set off at opposite ends of a 19-mile section between Box Canyon and White River, according to a park release. Mr. Birch had dropped his son off at the White River trailhead, drove to the Box Canyon trailhead, and left the car there while he hiked towards the White River trailhead.

At approximately 3:30 pm Saturday the two met midway on the trail near Indian Bar at around 6,600 feet above sea level.

"The son reported his father seemed well, although he was a bit tired," the park release said. "After arriving at the Box Canyon trailhead around midnight, the son picked up the car and drove to pick up his father at White River. When his father did not appear he notified park rangers at White River at 1:30 a.m."

A search Sunday that involved 10 ground crews and a helicopter team failed to find any sign of Mr. Birch.

"The entire trail, as well as high probability areas close to the point last seen, were covered that day without any signs of the missing hiker," the park reported.

On Monday, 53 searchers, along with an Everett Mountain Rescue dog team with air support from Northwest Helicopters, resumed the effort. This section of the Wonderland Trail is snow covered above 6,300 feet and patchy at other locations.