More than 20 people may be missing after a major flash flood at the Grand Canyon, the US National Park Service said on Sunday. The flood forced the evacuation of dozens of people and swept large boulders, metal structures and other debris into the Colorado River that runs through it, the park service said. The flooding in Bright Angel Creek, which flows into the river, happened on Saturday afternoon. Torrents of water wiped out footbridges over the creek and significantly altered the landscape,...