Chambers told CNN it was partly a mother-daughter trip to celebrate her 19th birthday. She trekked from the San Diego area, her mom from the Los Angeles suburb of Woodland Hills, to experience Zion in southwest Utah. Chambers said her very spiritual 38-year-old mother had become so overwhelmed by the gorge's beauty that she declared, "I've never been this close to God."Now Chambers is praying for the safe return of her mother, who has not been seen or heard from since October 6, when she embarked on a solo trip to Zion."It's getting critical — we just don't know how much food she brought, how much it will last," Chambers said."We need more volunteers to help us search, more hikers, rock climbers and trail guides. Especially trail guides who know Zion."Both the National Park Service and Chambers say the last time anyone saw Courtier, she was getting off a shuttle van at the Grotto area stop that leads to several Zion hiking trails, including the Emerald Pools, the Kayenta trail and the West Rim trail.But the question hanging over Zion's steep drop offs, knee-rattling switchbacks and slot canyons is: Where exactly did Courtier go?"There is a vastness," said Amanda Rowland, a public information officer for Zion National Park. "Zion has massive sandstone cliffs, there are slot canyons and a lot of wilderness. It's definitely a lot of area to cover. It's not just flat ground."The park service website lists Zion as 232 square miles of high plateaus, "a maze of narrow, deep, sandstone canyons, and the Virgin River and its tributaries." From the highest peak to the lowest canyon is about a 5,000 foot difference.Chambers thinks her mom is the type of person who could survive for more than a week outdoors in all of Zion's rugged glory. Courtier is a fit experienced hiker and a fighter, she says."If I could say anything to her, I would say just keep fighting," Chambers said. Courtier gave birth to Chambers when she was just 19 years old, the same age Kailey is now.Chambers said she usually talks to her mother almost every day and that's why she is so worried about not hearing from her for well over a week."This was her dream, to see national parks," Chambers said. "She lost her job as a nanny due to COVID-19. The family could not afford to keep paying her. She made that a positive thing — said that gave her the time to get out, see the parks."