At least 15 people are missing or unaccounted for after flash floods overwhelmed a remote area of the Grand Canyon, including a historic lodge near the bottom of the site, park officials said Sunday afternoon.

The National Park Service is asking for information about anyone who may have been hiking or backpacking along Bright Angel Creek in Arizona, as well as campers with plans to stay at Phantom Ranch or the Bright Angel Campground.

Officials are also trying to track down travelers who might have been stranded along the North Kaibab Trail.

Earlier Sunday, the number of those unaccounted for was at least 20. As of Sunday morning, 62 people had been evacuated from Phantom Ranch and the lower North Kaibab Trail. Additional evacuations from Phantom Ranch and the Cottonwood Campground were expected.

Park administrators also said that footbridges along Bright Angel Creek were destroyed, “eliminating hiker access across the creek,” and that certain Colorado River crossings were closed while damage is assessed.

“The flash flood resulted in significant impacts to infrastructure throughout Bright Angel Canyon,” the National Park Service said in a statement. “Grand Canyon National Park staff are continuing to assess damage to trails, bridges, utilities, facilities and other infrastructure.”

Phantom Ranch is accessible only by hiking, raft or mule transport. It has been a coveted Grand Canyon destination since it opened in 1922.

Colorado River traffic was also shut down because of the risk of floating debris.