About 15 hikers are unaccounted for after sudden flash flooding swept through Bright Angel Canyon and the Phantom Ranch area at about 14:30 local time on Saturday, triggering a major search and rescue response.

The National Park Service said 62 people have been airlifted out of the canyon so far, with additional evacuations expected, and reported no injuries to date. Park staff warned that flooding caused significant damage in parts of the inner canyon and that trails in the area have been closed.

One of those rescued, Nikki Baggs, 41, described a rapid change from calm to chaos. "The whole thing was terrifying," she said, adding she and two friends had been airlifted from the canyon late on Saturday. She said they had left their belongings at a Phantom Ranch cabin before stepping out, and watched water rush through the area. Baggs said they moved to higher ground when the rain began, then followed rangers to a ledge where they waited for hours before being evacuated at around 21:30 local time. She said they had been looking forward to dinner at Phantom Ranch but were grateful to rangers for what she called "a really uniquely coordinated effort."

The park service initially sought information about more than 20 people thought to be missing or unaccounted for, then revised that figure to approximately 15. Officials posted images showing footbridges destroyed by the flood and urged anyone who knew of hikers or backpackers in the Bright Angel Creek corridor on Saturday to contact authorities.

The NPS also warned that more thunderstorms and heavy rainfall were forecast for Sunday and Monday, which could produce additional flash flooding, debris flows, rockfall and rapidly changing trail and river conditions. The Bright Angel trail is the park's most popular hike; the Grand Canyon receives about five million visitors each year, underscoring the potential scale of disruption from further storms.

Rescue teams will remain on alert as weather forecasts raise the risk of further flooding and complicate efforts to reach and account for those still missing. Park closures and damage assessments are expected to continue while officials work to stabilise conditions and gather information from the public.