The McCallie School in Chattanooga released a statement Monday saying the missing hikers are eighth-grader Jackson Standefer and his step-grandmother.
His aunt posted to facebook that as the group were making their way through a water crossing Jackson and Julie's mother in law, 62 year old Carol, were swept away.
Chief Ranger Matt Vandzura of the National Park Service says two fellow hikers alerted authorities by setting off an emergency Global Positioning System locator beacon in the backcountry area below the canyon's North Rim. Authorities are searching for a 14-year-old boy and a 62-year-old woman missing in Grand Canyon National Park after they were swept down a creek while crossing it in a remote part of the park.
Lou-Ann Merrell is "a very experienced backpacker", McOmie said. "But given their skills and knowledge of the area, that will probably lead to the best possible outcome".
A call to the boot company's IN headquarters wasn't immediately returned Monday.
Vandzura said it's too early in the investigation to determine what went wrong.
According to information about hiking at the Thunder River/Tapeats Creek confluence, NPS says the area is known to be potentially hazardous in the spring.
It also said hikers can use a "sketchy, seldom-used trail" that lets them walk around the creek when the water is high, but that the path should be used only as a last resort.