A second person has been confirmed dead at Grand Canyon National Park after devastating flash floods over the weekend, park officials said Monday. Water from heavy rains swept through a remote area popular with hikers and campers.

More than a dozen people remained unaccounted for as search and recovery efforts continued along Bright Angel Creek, which runs from near the north rim of the canyon down to the Colorado River, the National Park Service said.

The agency warned that the search could be slowed by a new round of rain and thunderstorms forecast to hit the area on Monday.

Officials announced late Sunday that rescuers had found the first body, a 46-year-old man, near Crystal Rapids along the Colorado River. The Park Service provided no additional information about the second victim.