LEILA FADEL, HOST:
Over the weekend, thunderstorms caused a flash flood to race across the bottom of Arizona's Grand Canyon. Dozens of hikers had to be evacuated. And as of Sunday evening, just over a dozen people remain missing or unaccounted for, according to the National Park Service. Chris Clements of member station KNAU has more.
CHRIS CLEMENTS, BYLINE: Justin Johndrow is a meteorologist for the National Weather Service in Flagstaff. On Saturday afternoon, he watched as almost an inch of rain fell on parts of the Grand Canyon in about 30 minutes, something he says is out of the ordinary.
JUSTIN JOHNDROW: The amounts that we saw in that short period of time were fairly unusual for that exact location.
CLEMENTS: The resulting flood swept down a creek bed to the Colorado River, splintering bridges, demolishing houses and temporarily beaching boaters. Johndrow says the flood was partly caused by the terrain.
JOHNDROW: It's steep. It's rocky. So a lot of the rain that falls runs off, doesn't sink into the ground.
CLEMENTS: And the rain fell on a burn scar from last year's Dragon Bravo Fire, a wildfire that tore across the canyon's north rim. Several videos posted on Facebook show muddy red water surging down the canyon with a dull roar. The flood also mangled the only pipeline that delivers water from the bottom to hotels and businesses on the south rim. Author Craig Childs has both written about and been caught in flash floods in the Grand Canyon.
CRAIG CHILDS: They're incredibly loud and violent, and you can smell them. They smell of everything that's been carried down in the Grand Canyon.
CLEMENTS: Officials say they used helicopters to evacuate 62 people from the bottom of the canyon, with more evacuations to follow. Childs says his own brushes with previous floods were terrifying.
CHILDS: Just to be near it, to feel the walls shaking, to be struck in the face by all the muddy mist coming off - it's a pretty shocking and powerful thing to witness.
CLEMENTS: But he thinks that flood wasn't nearly as powerful as the one from this weekend.
For NPR News, I'm Chris Clements in Flagstaff.
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