AILSA CHANG, HOST:
California - a state that has been hammered this winter by storm after storm after storm. And now California is bracing for more, a series of atmospheric rivers that could bring more flooding and infrastructure damage to the already reeling state. NPR's Nathan Rott has been covering this unusually wet winter here in California and joins us now. Hey, Nate.
NATHAN ROTT, BYLINE: Hey, Ailsa.
CHANG: Hey. So can you just first explain for everybody what exactly is an atmospheric river?
ROTT: Well, they're all the rage this winter, apparently. This is going to be the 10th atmospheric river that California has experienced this season. And basically, atmospheric rivers are these - it's important to note they're totally normal weather phenomena, right? They occur...
CHANG: Yeah.
ROTT: ...All the time on the West Coast and many other parts of the world. And basically, they're a band of highly concentrated moisture in the air - you know, in the atmosphere that transport water from the tropics to higher latitudes, like where we are in southern California. So they really are like a river in the sky that can dump huge amounts of rain and snow, as we've seen with some of the widespread flooding that's happened here over the last few months.
CHANG: Exactly - huge amounts. And this latest atmospheric river - it's expected to start hitting today, right?
ROTT: Yeah, that's right. So forecasters are saying this latest atmospheric river will start to impact the state tonight, with the peak of the storm expected tomorrow, Friday. And to give you a sense of just how big the expected impact is, at a briefing earlier today, California's state meteorologist used the word astounding to describe...
CHANG: Wow.
ROTT: ...Some of the projected rain totals. Some parts of the central California coast could get up to eight inches of rain.
CHANG: Wow.
ROTT: Some major mountain passes could get more than a hundred inches of snow. So it's going to be a very heavy couple of days we're looking at.
CHANG: I mean, this is happening while some parts of California are still literally digging themselves out from earlier storms.
ROTT: Yeah, literally is - it is appropriately used there. Here's what I heard from Sintia Kawasaki-Yee, a spokesperson at Sequoia and Kings Canyon National Park earlier today.
SINTIA KAWASAKI-YEE: We have 12 feet of snow in some areas. And so we are digging out vehicles, equipment, access points to our homes for residents that live in these areas.
ROTT: And roofs, she said, is actually a really big concern right now because this atmospheric river is expected to bring warmer conditions than previous ones. So at some high elevation places, they could see rain, not snow. And, you know, you don't have to shovel a whole lot of snow in your life to know that wet snow is a heck of a lot heavier than dry. The other big issue the rain could bring is snow melt and runoff. Warm rain on snow can help speed up melting, and California snows - California's mountains are just packed with all of this snow right now. So there's the potential for major runoff...
CHANG: Yeah.
ROTT: ...Localized flooding along streams and rivers, especially along the Sierra Nevada mountains.
CHANG: So how is the state preparing for these impacts?
ROTT: Yeah, so reservoir operators are already increasing releases from some of the state's reservoirs to accommodate for the expected runoff. Remember; nearly all of the state was in a drought just a few months ago, so many of these reservoirs have room to fill. Flood warnings have been issued in many parts of the state. Emergency response crews are getting ready for a whole spate of potential road closures, landslides, avalanches and all the other, you know, normal inconveniences you'd expect from a storm of this magnitude.
CHANG: And real quick, Nate, you mentioned the drought. I mean, we're hearing people wonder, oh, maybe the drought is over in California. But yeah, right. Right?
ROTT: You're right, yeah. It's not. The meeting - at the briefing today, basically, the head of the California's Department of Water Resources said the state's groundwater reservoirs are still critically low, and so it will take more than one wet winter for those to really recover.
CHANG: That is NPR's Nathan Rott in Ventura, Calif. Thank you, Nate.
ROTT: Yeah, thank you. Transcript provided by NPR, Copyright NPR.
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