MOFFAT COUNTY, Colo. (CBS4) – Officials in Moffat County in the northwestern corner of Colorado confirmed an apparent drowning on the Green River near Echo Park at Dinosaur National Monument.

The drowning was first reported by a private rafting company Saturday afternoon. It occurred at Triplet Falls in a very remote part of the river.

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“Four members of a 16-member private river trip fell into the water after their raft flipped at an area of Triplet Falls called the Birth Canal,” Dan Johnson with Dinosaur National Monument said in a statement.

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Three of the rafters were able to swim to safety but the fourth was last seen in the water at the base of the rapids but then disappeared. He’s been identified as a 34-year-old man from Denver but his name hasn’t been released.

“The group stayed at the location for several hours searching for him before continuing downstream for assistance,” Johnson said.

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Crews from Search and Rescue staff from Dinosaur National Monument, Moffat County Sheriff’s Office and Colorado Parks and Wildlife have been attempting to get to the area to launch a search before nightfall on Sunday but will now travel by boat to the location and begin searching a daybreak.