Police have abandoned the ground search for a man who disappeared over Washington's Cascade Mountains on Thursday after making a wingsuit jump from a helicopter at 6,500 feet. Based on flight records and cell phone data, Kurt Ruppert of Lake City, Florida, is thought to have disappeared somewhere around 4,200-foot Mount Si. No one saw Ruppert jump or whether he was able to deploy his parachute. "The guys on the ground could not see where he jumped from their angle, and the pilot couldn't see when he went out the door because he was focused on flying," a King County Sheriff’s spokeswoman said. Authorities abandoned the search due to the difficulty in exploring the remaining cliffs and ravines and the improbability that Ruppert could have survived the weekend's cold temperatures. Friends described Ruppert as an experienced skydiver and comfortable using a wingsuit.