The Phantom Ranch area of Grand Canyon National Park. Officials said more than 20 people are missing following flash flooding in areas of the park. Photo courtesy Parth Desai/National Park Service.

Aug. 30 (UPI) -- More than 20 people are missing after "significant" flash flooding struck areas around the Grand Canyon, officials said Sunday.

The National Park Service asked for those who know of hikers or backpackers who were in the Grand Canyon National Park areas of Bright Angel Canyon and Phantom Ranch when the flooding hit to contact park officials.

"Grand Canyon National Park staff, in coordination with the Arizona Department of Public Safety, are continuing evacuation and response efforts and working to account for individuals who may have been in the affected area," NPS said in a statement.

The NPS said it is also searching for anyone who may have been on the North Kaibab Trail from the North Kaibab Trailhead to Phantom Ranch, staying at Bright Angel Campground, or traveling or staying in the area known as "the Box" north of Phantom Ranch.