A search and rescue mission was ongoing Monday at Grand Canyon National Park in Arizona for two backcountry hikers swept down Tapeats Creek.

On Saturday evening the National Park Service received an alert from a personal locating beacon in a backcountry area of the park near the confluence of Tapeats Creek and Thunder River. An Arizona Department of Public Safety helicopter flew to the location, where a hiking party reported two members of their party missing.

The hiking party reported that the two hikers were last seen crossing Tapeats Creek below the confluence with Thunder River when they lost footing and were swept down Tapeats Creek.

The first hiker is described as a 62-year-old woman. She was last seen wearing khaki zip-off shorts, a blue/green button down short-sleeve shirt, and blue water shoes. She was carrying a homemade blue backpack with a maroon fleece and hiking poles attached.

With her was a 14-year-old boy. He was last seen wearing black Nike shorts, a long-sleeve white Columbia t-shirt, and navy blue Chaco sandals. He was carrying a sage green backpack.

Park Service crews were flown to the scene Sunday and were searching the Tapeats Creek area. Backcountry hiking groups and Colorado River trips in the area have also been alerted.