The body belonging to John Arum, an experienced mountain climber, was seen from a National Park Service helicopter at about the 7,700-foot level of the 8,500-foot Storm King mountain, park spokeswoman Kerry Olson said.
Previous flights had been made in this area, but recent snow melt made it possible to locate the 49-year-old Seattle environmental attorney's body on Friday, she said.
It wasn't possible to either reach or retrieve the body, but Olson said it was clear to searchers in the helicopter that Arum was dead.
"There was no doubt of that," she said, adding it appeared that Arum had fallen.
The search began Monday after Arum failed to return from a solo weekend trip to climb the mountain, which family members said was part of his goal of reaching the summit of the 100 highest peaks in the state.
"His plan was to climb Storm King on Saturday, so it's probably a safe assumption that he fell that day," Olson said.
Arum's larger backpack was found Wednesday on a trail on the mountain's less arduous south side, Olson said. His small day pack was found Thursday and Olson said his body was found about 300 feet below that spot in an extremely steep area with a lot of loose rock.
About 20 people, some using trained search dogs, were out earlier Friday, along with four helicopters, two of them King County sheriff's aircraft with heat-seeking equipment. Counting coordinators and support workers, about 50 people were involved in the search, Olson said.
National Park Service workers were trying to develop a plan to recover the body, which is in an area so difficult "that people can't rappel down or climb up to it," she said.
Friday's weather was clear, with temperatures in the 80s. However, the National Weather Service has forecast that clouds will move in with a chance of rain Saturday.
Earlier this week, Bob Arum left Los Angeles to join park rangers coordinating the effort. He had been on a three-city tour promoting the Nov. 13 fight between Manny Pacquiao and Antonio Margarito at Cowboys Stadium in Arlington, Texas. His stepson, Todd duBoef, took over the tour that also stopped in New York and Dallas.