Los Angeles Wildfires Burn For Days, Stoked By Santa Ana Winds

IRA FLATOW: This is Science Friday. I’m Ira Flatow. As we’ve all been watching, Los Angeles County has been battered by devastating wildfires. Tens of thousands of acres have burned, and thousands of people have been forced to flee their homes.

So why are these fires raging like this and burning down homes, some of them not even in forests? It has to do with the wind. Joining me to tell us about this and other science news of the week is Umair Irfan, senior correspondent at Vox covering science, climate change, and the environment. He’s based in Washington, DC. Welcome back to Science Friday.

UMAIR IRFAN: Hey, Ira. Thanks for having me.

IRA FLATOW: Nice to have you. OK, let’s get into these California fires. I talked about the wind. What factors are coming to make this place so ripe for fires right now?

UMAIR IRFAN: Right. Theses winds are actually a seasonal phenomenon. They’re typically called the Santa Ana winds. And usually in the wintertime, they start to pick up. They blow from the Northeast towards the Southwest and towards Los Angeles.

And they occur basically when you have this air over the mountains start to roll downhill. And as they build up pressure, the air dries out. It speeds up, and they start gusting towards cities like Los Angeles.

This year, though, they’ve been exceptionally strong, with gusts reaching up to 100 miles an hour. And that’s part and because of this high pressure system that has kind of parked over the mountains that is helping squeeze more air outward and westward towards the city, and that’s adding this additional gust.

Meteorologists were able to actually see this coming. They’ve been warning about very, very high winds this year since the beginning of the year. And then on top of that, Los Angeles, the area, saw an exceptionally dry start to its winter, which meant that a lot of the vegetation around it, which is mainly grasslands and chaparral, with a few trees here and there, it dried out very quickly.

And the key thing to note is that while this winter was very dry, the prior winter was very, very wet. And so over the past year, basically through most of 2024, there was this bumper crop of grasses and fast-growing shrubs that built up. It dried out in the record heat. And now, in this dry winter, and the combination of high winds, has created basically the ideal conditions for a major fire.

IRA FLATOW: Wow. We’re keeping all of you out in Southern California in our hearts. But for those of us on the other side of the country, many of us are dealing with an extreme cold snap. Give us the lowdown on that winter air.

UMAIR IRFAN: Right. And there’s this interconnection between both the fires and the cold snap across much of the country as well, and that is this phenomenon called the jet stream. This is a high-altitude, fast-moving band of air. It normally circles the Arctic in an even circle. But every now and then as it weakens, it starts to meander and snake across parts of the Northern hemisphere.

So as it pushes down in some areas, like it’s doing over the Eastern United States, it lets cold Arctic air start to spill over and help fuel these bouts of extreme cold. And then in other parts of the country, it starts to move upward and allows warm air to hold in place. And that’s what we’re seeing across the West of the US. And so that’s kind of the interconnection here.

And so on the East Coast, yes, we’re seeing this burst of cold air. And scientists expect that potentially if the Arctic continues to warm, it can cause these kinds of destabilization events to happen more often.

IRA FLATOW: That may seem strange in people’s minds. It’s getting warmer, but we’re getting these polar vortexes.

UMAIR IRFAN: Right. I mean, the key thing to remember is that the Arctic is warming about four times faster than the rest of the planet. And so a tiny bit of warming on the rest of the planet usually means a lot more warming there. And “warm,” quote unquote, air in the Arctic is still frigid by our standards. So even warmish Arctic air, when it spills down, can induce a lot of ice and snow when it reaches the lower 48.

IRA FLATOW: All right. Let’s move on to some virus news. And actually, unbelievably, some good news. There’s a viral outbreak in China that’s actually not as bad as many experts feared. Tell us about this.

UMAIR IRFAN: Right. There was some news going around that there was this spike in this respiratory infection caused by this virus called the human metapneumovirus, or HMPV. And there was some information and misinformation and some viral reports that there was another outbreak that was happening in China of another respiratory virus that was raising a bunch of alarm.

But this week, health officials at the Chinese Centers for Disease Control and the World Health Organization, they analyzed the data. And they said that basically what we’re looking at is an ordinary seasonal uptick in respiratory viruses in China.

Now, the HMPV cases are making up a larger share of these respiratory infections. But the overall rate of infections is basically what they would expect for this time of year. That essentially, as more people gather indoors in the winter, colds and other kinds of infections will spread more readily. And that’s what we’re seeing happening right now. And this virus itself tends to cause fairly mild cold-like symptoms. So it’s not severe even if you get it.

IRA FLATOW: OK. It’s good that we can breathe a sigh of relief about this virus because this is the virus season. And unfortunately, there’s some not great news about another virus, the norovirus. Tell us about that one.

UMAIR IRFAN: Right. The Centers for Disease Control reported this week that actually the norovirus levels in the US are unusually high right now, probably at the highest levels they’ve seen in more than a decade. In the real world, the numbers might be even higher because this is just based on cases that have been reported or have interacted with the medical system.

The norovirus is a stomach bug. It causes gastrointestinal problems. It causes vomiting and diarrhea and a lot of other unpleasantness. And we do see it tend to rise more in the winter. But part of the reason we’re seeing an unusual spike right now is maybe some of the consequences of the COVID-19 pandemic.

Basically, immunity to norovirus usually lasts a couple years. But during COVID-19, when people were isolating, there was much less transmission of norovirus. And so a lot of that natural immunity that had built up for a while had died down. And then as people started gathering once again, that disease has now come roaring back.

IRA FLATOW: And how do you protect yourself from this miserable, miserable virus?

UMAIR IRFAN: Well, again, the basic measures that we all know and love. I mean, washing your hands appropriately. This is something that can be transmitted through your hands and through contact with people who are infected. And then also, maintain good hygiene, distancing, and wearing masks if you’re not feeling well and wearing masks around people who are likely to be infectious.

IRA FLATOW: Right. All right. Let’s move on to a bit of political news. As we know, we’re going to have a change in presidents this month. But President Biden, at the 11th hour, has banned new oil and gas drilling along most of the US coasts in a way that would be hard for President Trump to reverse. Tell me about that.

UMAIR IRFAN: Right. Basically, they issued this new ban on drilling in coastal waters across basically 625 million acres. This includes pretty much the entire East Coast and the West Coast, as well as parts of the Gulf of Mexico and parts of Alaska.

These are areas where we don’t see much drilling to begin with, and we haven’t seen much oil and gas industry interest. But this designation also basically kind of closes the door to that. That essentially sends a signal to the industry that this is going to be something that’s going to be off limits for the foreseeable future.

The White House also said that they’re going to maintain federal protections for 2,000 grizzly bears in the Rocky Mountains. The population of these bears has recovered pretty extensively over the past few decades, and their range is expanding, but it’s also leading to more conflicts with locals. And so they’ve been seeking approval to hunt and to contain these bears. But these federal protections mean that they’re going to be off limits for the foreseeable future.

And in addition to that, President Biden this week also announced new monument designations in California, protecting about 800,000 acres of new land, and for similar reasons, to protect them against new oil and gas development, and trying to use legal mechanisms that they hope won’t be easily overturned by the next administration. Although, President-elect Trump has already said that he wants to reverse a lot of these protections.

IRA FLATOW: OK, let’s talk about another story that’s been in the news this week. There has been a review of 74 medical studies that links higher fluoride exposure to lower IQ in kids, but it might not be as straightforward as that. What does this survey say, and why are people pushing back on it?

UMAIR IRFAN: Well, the authors of this study that was published this week in JAMA Pediatrics note themselves that basically, the main conclusion of this review is that the data out there just isn’t very good. They looked at 74 medical studies, as you noted, looking at these links between lower IQ and children, and basically found that the quality of the research isn’t very good.

All of the research is based on studies that were conducted outside of the United States, most of them are in China. And they were conducted in communities that have much higher levels of fluoride exposure than you would find in the United States. And the quality of those studies are not very good.

And so while they did show a link when you pull them all together, they did issue this major caveat that essentially this is not a very robust finding. And that if you wanted to make any kind of statement about this, you really need to do a lot more research.

IRA FLATOW: Right. Right. All right, let’s lighten up a little bit at the end here with a topic that we all love– dinosaurs, a new dinosaur. What’s going on here?

UMAIR IRFAN: Well, right. Researchers this week at the University of Wisconsin-Madison described these fossils that kind of upend the timeline of when they think dinosaurs originated. Basically, millions of years ago, most of the continents were pushed together in this giant supercontinent called Pangaea. And the prevailing theory was that essentially, dinosaurs originated in the Southern part of the continent and millions of years ahead before they started moving and migrating further and further North.

But these new fossils, they were found in essentially an area that was in the Northern Hemisphere of the supercontinent around the same time– basically, around 230 million years old. And that indicates that essentially, the dinosaurs have been roaming much further and more widely earlier than they had expected.

And this dinosaur, it’s about the size of a chicken with a long tail. The name of it is Ahvaytum bahndooiveche. It’s from the name drawn from the Shoshone language, which means long ago dinosaur. But basically, this finding kind of really forces them to reevaluate exactly when dinosaurs originated. And perhaps they may have started spreading across the Earth even earlier than we realized.

IRA FLATOW: Wow. Wow. Love our dino news, Umair. Thank you for taking time to be with us today.

UMAIR IRFAN: My pleasure. Thanks for having me.

IRA FLATOW: Umair Irfan, senior correspondent at Vox covering science, climate change, and the environment. He’s based in Washington, DC.

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