ROCKY MOUNTAIN NATIONAL PARK, Colo.—Skeletal remains found in Colorado’s Rocky Mountain National Park are believed to be those of a 27-year-old man from West Germany who disappeared during a multi-day mountaineering trip nearly 40 years ago, park officials said Thursday. Rudi Moder, an experienced winter mountaineer who was living in Fort Collins, started his excursion over Thunder Pass and into the park Feb. 13, 1983. His roommate reported him overdue Feb. 19, 1983. Searchers started looking for Moder the following day, but more than a foot (30 centimeters) of fresh snow prevented them from immediately finding tracks or other clues. The only major clues found during the four-day search were a food cache belonging to Moder that was discovered at the mouth of a canyon in the northwest corner of the park and a nearby snow cave with Moder’s sleeping bag and other gear and items inside. The search included …