ELISSA NADWORNY, HOST:
California is getting drenched by what meteorologists are calling a life-threatening storm system. It's the second major winter storm to hit the West Coast in a week, only this one is stronger and is poised to mostly affect central and southern California, where NPR climate correspondent Nathan Rott calls home. Good morning, Nate.
NATHAN ROTT, BYLINE: Hey, Elissa.
NADWORNY: So you're in Ventura. What is it like there?
ROTT: All right, so we're still in the, like, relative calm before the storm stage, I would say - a little rain, lots of wind. Further north of us here on the Central Coast, the National Weather Service is warning that there could be hurricane-force winds later today, which is super, super rare for California. Obviously that's causing power outage concerns and all that. But the main thing that everyone's really worried about right now is the amount of rain that's expected. The area that I'm in is likely to get upwards of six inches of rain in the next couple of days. Some places are forecast to have more than 10. And that's especially concerning because so much of the ground in Southern California is already saturated from the first atmospheric river that hit California last week. So there's potential for flooding and debris flows, rockslides, pretty much all the way from Santa Barbara to Los Angeles.
NADWORNY: OK, you're saying atmospheric river. What actually is an atmospheric river?
ROTT: (Laughter) That's a good question. OK, so, the way that scientists have described it to me is to imagine a river of moisture in the sky. So, like, a band of highly concentrated water vapor, a river of water vapor, that's flowing with moisture from warmer tropic areas to cooler latitudes. So this one is transporting water from Hawaii to the West Coast. That's why you might hear it be called a Pineapple Express - weird name.
NADWORNY: Yes. What's with this name, Pineapple Express?
ROTT: Yeah. Look, that's the meteorological definition. It's not a movie or a flower reference. But it is important to know, Elissa, that atmospheric rivers are totally normal. Pineapple Express - it's normal. They're natural phenomena like hurricanes and wildfires. And they do bring the western U.S. and California most of the water it needs to grow crops and keep the faucets running in homes like mine, so they're important. That said, they can be destructive. You know, a series of atmospheric rivers last year caused billions of dollars in damages in California, flooding a lot of areas, including the areas surrounding my favorite surf shop here in Ventura. So there's a lot to be concerned about.
NADWORNY: So we hear about all sorts of natural disasters getting more deadly, more damaging because of climate change. Is that what's happening here?
ROTT: So this is interesting. You know, it's widely accepted - like, we know - right? - that warmer air holds more moisture, and that by burning fossil fuels, humans are warming the Earth's atmosphere. So rain events, hurricanes, for examples, are becoming more intense in some places. With atmospheric rivers, it's a little less clear. So I talked to Alexander Gershunov, a research meteorologist at the Scripps Institution of Oceanography at the University of California, San Diego. We talked about this the other day, and he said they expect to see atmospheric rivers to get more intense, like hurricanes, with climate change.
ALEXANDER GERSHUNOV: It's almost certain to happen. But we have not detected a signal yet. There is no observed trend yet.
ROTT: So they expect it, but they haven't seen it. When we might see it, he says, is still pretty unclear. It could happen this year. This could be the start of it. It could be years away. It could be decades. There's a lot of research going into atmospheric rivers right now, though, and I think that is a reflection of how serious and dangerous they can be, like we're seeing right now.
NADWORNY: That's NPR's Nathan Rott in Ventura, Calif. Stay dry, Nate.
ROTT: Hey, thank you, Elissa. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
