The Hollywood sign stands sentry above Los Angeles, watching its embers dance through the January night like fickle stars. As glistening debris floats past million-dollar mansions on warm air, emergency crews battle a fire that shouldn’t exist – not in winter, not here, not now.
Two thousand miles to the east, in America’s heartland, a different kind of emergency is occurring. Mercury is plummeting to depths not seen in a decade. Wind chills reach below 40 degrees. Airlines have hundreds of ground flights. Roads become dangerous ribbons of ice. People are flocking to warming centers, while the arctic winds howl like hungry ghosts outside.
fire and ice. A country divided into two.
We’ve been here before. In the winter of 2013-2014, the first dramatic chapter of this story was written. California is experiencing its worst drought in 1,200 years. The drought was so severe that the vines in America’s fruit baskets withered. Meanwhile, the eastern United States was reeling from what the media called “a return to the polar vortex.” The temperature fluctuations between California and the East Coast that winter were unlike anything seen in modern records.
That winter changed the way we think about the climate. Our research at Utah State University revealed something interesting. That is, the atmosphere is behaving like a river crashing against a rock. Just as water creates waves when it flows around obstacles, our atmosphere also creates waves when it encounters mountains or ocean heating patterns. These are not just waves, but giant atmospheric ripples that span continents.
Think of the jet stream, the river of air flowing over our heads, as a cosmic garden hose. If it is straight, the weather pattern continues to progress normally. But recently something has caused it to wobble more dramatically. Previous research has found the cause. The western Pacific Ocean is warming significantly, creating an atmospheric domino effect that extends all the way to North America.
Here’s how it works: The warm western Pacific Ocean acts like a hot plate in the atmosphere, creating updrafts that cause waves to ripple eastward, like stones dropped into a pond. These waves travel along the jet stream, the cosmic highway through which atmospheric turbulence travels. Once these waves reach North America, they can become “stuck” in certain patterns, causing persistent extreme weather on both coasts or on one coast and the Midwest.
By 2017, we were seeing another manifestation of this pattern, but with a twist. Atmospheric rivers, literally rivers of water vapor in the sky, swept through the state, dramatically changing California from drought to deluge. Then, in January 2018, the eastern U.S. experienced another deep freeze, while the western region remained warm and dry. The pattern became more pronounced and more persistent.
The evidence for this amplification is not just anecdotal. Our research shows that the intensity of these winter extremes has increased by about 20% since the late 20th century. We can literally see it in the form of a jet stream, which now regularly curves into deeper waves than it did just a few decades ago. It’s like a river that used to flow relatively straight but begins to meander more violently.
The physics behind this is clear. Warming in the Western Pacific is not just a random fluctuation. It’s part of a larger pattern of climate change. This warming creates more powerful “wave trains” of atmospheric energy that propagate along the jet stream toward North America. When these waves interact with mountains and existing weather patterns, they create a persistent seesaw effect between coasts.
Now, in 2025, we are seeing the same pattern play out again, but with even greater intensity. The Palisades Fire is the most destructive winter fire in Los Angeles history, and the eastern United States is facing its largest winter storm in a decade. This is no coincidence. It’s the same atmospheric pattern we’ve been tracking for years, and its muscles are contracting with unprecedented strength.
The changes we are seeing are no longer subtle. Our latest research has identified certain atmospheric fingerprints that are becoming more frequent and stronger across the western United States. This is a unique three-part wave created in the atmosphere that creates the perfect conditions for fires to start. These waves have become more frequent since 1980 due to the warming of the subtropical eastern Pacific Ocean.
This pattern, known as weather conditions, has some negative effects on the landscape. This means that the atmospheric thirst for moisture increases dramatically. Once this weather pattern takes hold, it’s not just the lack of rainfall that worsens the drought. The atmosphere itself pulls water from the soil, vegetation, everything, turning California’s landscape into a crater. This pattern can last for weeks, creating fire conditions even during the wettest and coldest months of the year.
What is particularly worrying is how this pattern is reinforced. As the landscape dries out, it tends to warm up, strengthening the atmospheric ridges that caused the dryness in the first place. It’s a vicious cycle where winter becomes an extension of fire season. In 2014, this pattern was so intense that NASA satellites were able to observe California’s mountains rising as the weight of water was literally lifted from the landscape.
But understanding these patterns gives us power. In 2014, we were caught off guard. By 2017, I was ready, but I was still surprised by the intensity. At least we can see it coming, with 5 million Californians currently under red flag warnings and 60 million easterners facing winter storm warnings. Weather forecasters can warn communities several days in advance. Emergency managers can deploy resources before they are needed. The community can prepare.
The question is not whether these patterns will continue. Our research shows that they do. The question is how do we write the next chapter, how do we adapt to this new normal where fire seasons know no calendar and the very patterns of our atmosphere are being rewritten by a warming world? That’s it.
Robert Frost once wondered whether the world would end in fire or ice. This winter, America doesn’t have to choose. Understanding new patterns in climate will not reduce its dramatic effects, but it will give us a fighting chance to prepare for what comes next.
Shih-Yu Simon Wang is a professor of climate science at Utah State University.
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