The National Park Service warned of additional thunderstorms and heavy rainfall that could trigger further flash flooding. Read more at straitstimes.com. Read more at straitstimes.com.

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

More than 20 people may be missing following a flash flood in Grand Canyon National Park in Arizona, according to park officials.

National Park Service officials said it was seeking information about 15 people who may be missing or unaccounted for after Saturday's flash flooding.

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