Yellowstone National Park – Searchers in Yellowstone National Park have been unable to locate a missing boy scout, who fell into the Yellowstone River Friday evening. The park says more then 250 people, a park helicopter, and a team of kayakers were employed in the search Sunday for 13-year old Luke Sanburg of Helena, Montana. The Park Service says Sanburg and other members of his scout troop were pushing logs into the Yellowstone River when he was clipped by one of the logs, and swept into the fast-moving water. Searchers have only been able to find a pair of white tennis shoes matching the description of what the boy was wearing when he fell into the river. The park plans to continue searching by air and on the ground Monday, but the number of park staff could be scaled back to best utilize resources.