Authorities are searching for Jackson Standefer, 14, and Lou-Ann Merrell, 62, after the pair lost their footing Saturday and fell into the water during a family trip in a remote area of the Arizona park.
Mark McOmie, Jackson's uncle, said the water roars down through rocks, so the family is hoping the two could be on a boulder or have found a cave for shelter.
Authorities searched Grand Canyon National Park on Monday, April 17, 2017, for eighth-grader Standefer and his step-grandmother who were swept away as they tried to cross a creek during a family trip in a remote part of the park.
This story has been corrected to show Randy Merrell's name was misspelled Merrill. The pair were hiking below canyon's North Rim with Randy Merrell and Jackson Standefer's mom, Julie Standefer.
Nelson said in an Associated Press interview on Tuesday that the creek where Merrell and Standefer went missing can get heavy water flow after the winter, when snow from the North Rim melts and travels down the canyon.
The McCallie School in Chattanooga, Tennessee, released a statement Monday saying the missing hikers are eighth-grader Jackson Standefer and his stepgrandmother.
One of those missing hikers is the wife of the founder of the Merrell Boot Company, according to the Associated Press.
The Park Service resumed the search Monday with ground crews, a helicopter and a drone.
He said that area is particularly hot during the day and doesn't cool off very much because of the geology.
"We're really just looking in the water and areas where someone maybe would have been able to get out", Martin said.
Zwiers also said in the written statement that the company was grateful to the searchers and that he continues to be hopeful.
"The bad part is that they don't have their gear", said McOmie.
This story has been corrected to show that the family of Jackson Standefer, and not the Merrell company, is offering to provide a military-grade drone. The search for Jackson and LouAnn continues, and the overwhelming support has helped us remain positive throughout this process.
The Grand Canyon is consistently one of the most popular attractions in the United States, drawing almost 6 million people a year ago.
Thank you as always for respecting the family's need for privacy as we work through this hard time.
Tapeats Creek, where Lou-Ann Merrell and Jackson Standefer lost their footing Saturday during a family trip, is not particularly hard to hike, said Chris Forsyth, president of the Grand Canyon Hikers & Backpackers Association board.
McOmie said searchers have found their backpacks with belongings inside, which the family has interpreted with mixed feelings.