SCOTT SIMON, HOST:
The first-ever tropical storm watch is in effect for Southern California because of Hurricane Hilary, which is off Mexico's west coast and making its way up toward the Baja Peninsula. It is expected to pass into the U.S. Sunday evening as a tropical storm and if so, will be the first since September 1939. The National Weather Service says, quote, "life-threatening flooding is likely," unquote. And climate science tells us that human-caused global warming can make intense storms like Hilary more common. NPR's climate reporter Julia Simon joins us. Julia, thanks so much for being with us.
JULIA SIMON, BYLINE: Thank you, Scott.
S SIMON: I guess we cannot officially say yet this storm is the result of climate change, but we can examine the link between humanity and severe weather, can't we?
J SIMON: Yes. And we know that humans burning fossil fuels means that the whole earth is heating up, and oceans store a lot of that heat. When ocean water is extra hot, it's easier for big hurricanes to form. That hot water is sort of a fuel, an energy source for hurricanes. So it makes it more likely that an intense storm like Hurricane Hilary will form.
S SIMON: And how hot are ocean waters right now?
J SIMON: The ocean is a lot warmer than usual this summer. Forty percent of the world's oceans are experiencing heat waves right now. According to federal researchers, that's because of a natural climate pattern called El Nino and human-caused climate change. Part of the ocean that this storm formed over is around Baja California, Mexico, in the Pacific. Temperature anomalies there are part of what's been fueling this storm, says UCLA climate scientist Daniel Swain.
DANIEL SWAIN: The ocean temperatures off the coast of Baja California are much warmer than usual right now - as much as 2 to 4 centigrade or 3 to 6 Fahrenheit. That's a pretty significant increment of additional hurricane fuel.
J SIMON: And we're likely to see intense rain in the coming days in Southern California and the Southwest region.
S SIMON: I mean, big storms do sometimes occur on the West Coast. But again, this is the first time that a tropical storm watch has been issued for Southern California. Is this area - and we should note, that's where you are right now...
J SIMON: I am.
S SIMON: ...Prepared?
J SIMON: Forecasters have said that the storm could dump a year's worth of rain for the Southwest over a couple of days. Los Angeles officials had a press conference yesterday about storm preparations. They said they're working to help the unhoused community that live in vulnerable places. Here's Los Angeles County Sheriff Robert Luna.
ROBERT LUNA: Our department's personnel are also working to deploy personnel in the riverbeds to contact our unhoused population, our unhoused community, and connect them with interim housing resources.
J SIMON: Luna also noted some additional precautions for communities at risk of landslides, like an area called Palos Verdes, which was already seeing landslides this summer.
S SIMON: Julia, what should people in the path of the storm be looking out for right now, particularly when they're not accustomed to this kind of rainfall?
J SIMON: Flooding is the No. 1 killer in hurricanes. So thing to remember - don't drive into standing water. Turn around, don't drown is the message. There's a high probability of flash flooding on Sunday and Monday in Southern California. So people here should pay attention to flood alerts, evacuation orders - also a risk of landslide, especially in places with burn scars from wildfires.
There's still a lot of uncertainty about the exact course of the storm. But generally, make sure you have alerts set up on your phone, charge your devices and get gas now. LA County officials said people can get sandbags at local fire stations. So make sure you have water, food and are checking in with your loved ones and neighbors. Have your bags packed for your family and your pets if you need to evacuate.
S SIMON: And Julia, big storms are going to be part of our future. What advice is there that people can take to protect themselves from devastation?
J SIMON: Humans have agency here. It's really important that as we build new infrastructure, we think about the possibility of intense storms like this one that maybe have not hit before. If humans stop emitting greenhouse gases today, there still will be some warming into mid-century baked in. But by cutting climate pollution now, we can avoid worse outcomes in the future.
S SIMON: Julia Simon of NPR's Climate Desk. Thanks so much.
J SIMON: Thank you. Transcript provided by NPR, Copyright NPR.
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