RIVERTON, Wyo. (AP) — Authorities say one person is dead and another is critically injured after they either jumped or fell from a roadway over a Wyoming dam.

One person was confirmed dead at the scene and another had life-threatening injuries. Emergency response agencies say the incident was reported Friday afternoon.

Investigators say it's not yet clear how or why the two people fell from Diversion Dam in Fremont County.

Several agencies responded on Friday, including fire and ambulance crews, search and rescue teams, two air ambulance helicopters and local law enforcement.