More than 20 people are thought to be missing or unaccounted for after flash flooding swept through parts of the Grand Canyon.

It hit at around 14:30 local time (22:30 BST) on Saturday in Bright Angel Canyon and Phantom Ranch area, according to the National Park Service (NPS).

Sixty-two people have so far been airlifted out of the area, with more expected to follow. No injuries have been reported.

The NPS said flooding had caused significant damage in some areas and that trails in the area have been closed.

It warned that more thunderstorms and heavy rainfall were forecast for Sunday and Monday, which could lead to “additional flash flooding, debris flows, rockfall and changing trail and river conditions”.

The NPS asked anyone who knew of hikers or backpackers who were in the inner canyon along the Bright Angel Creek corridor on Saturday to get in touch.

The Grand Canyon is one of the most popular national parks in the US, with about five million people visiting each year. The Bright Angel trail is its most popular hike.

The Phantom Ranch area can only be reached by foot, mule or by rafting the Colorado River, according to Grand Canyon National Park Lodges.