At least 15 people are missing or unaccounted for after flash floods overwhelmed a remote area of the Grand Canyon. https://www.nbcnews.com/news/us-news/20-missing-grand-canyon-extreme-flash-flooding-rcna595197?taid=6a94bb744f5fab00011020d1&utm_campaign=trueanthem&utm_medium=social&utm_source=twitter