Get Ready for a Year of Chaotic Weather in the US

Despite being declared the third-hottest year on record, 2025 was a relatively quiet year for climate disasters in the US. No major hurricanes made landfall, while the total number of acres burned in wildfires last year—a way of measuring the intensity of wildfire season—fell below the 10-year average.

But starting this week, the West is experiencing what looks to be a record-breaking heat wave, while forecasting models predict that a strong El Niño event is likely to emerge later this year. These two unrelated phenomena could set the stage for a long stretch of unpredictable and extreme weather reaching into next year, compounding the effects of a climate that’s getting hotter and hotter thanks to human activity.

First, there’s the heat. Beginning this week and heading into next, a massive ridge of high-pressure air will bring record-breaking temperatures to the American West. The National Weather Service predicts that temperature records across multiple states are set to be broken in dozens of locations, stretching as far east as Missouri and Tennessee. The NWS has issued heat warnings for parts of California, Arizona, and Nevada, as well as fire warnings for parts of Wyoming, Nebraska, South Dakota, and Colorado.

“This will be the single strongest ridge we’ve observed outside of summer in any month,” says Daniel Swain, a climate scientist at the University of California Agriculture and Natural Resources.

The other remarkable thing about this heat wave, Swain says, is just how long it’s going to last. “This is not a day or two of extreme heat,” he says. “We've already in some of these places been seeing record highs every day for a week, and we expect to see them every day for another at least seven to 10 days.” The later end of March will be much more intense, with temperatures in some places breaking April and May records. “There aren't that many weather patterns that can result in an 85- or 90-degree temperature in San Francisco, Salt Lake City, and Denver in the same week.”

This late winter heat wave is adding on to an already warm winter in the West—with big implications for the summer. A month ago, snowpack levels across multiple states were at record lows thanks to warmer-than-average temperatures. According to data provided by the Department of Agriculture, snowpack levels were still sitting below 50 percent of average across many Western states. Snowpack is a critical natural reservoir for rivers in the West; between 60 to 70 percent of the region’s water supply in many areas comes from melting snow. Low snowpack is a bad sign for already-stressed rivers like the Colorado, which supplies water for 40 million people in seven states.

The ongoing heat wave, Swain says, will more than likely make conditions even worse. “April 1st is typically the point at which snowpack would be, at least historically, at its peak,” he says. Even if temperatures cool off until summer, these low snowpack levels are also a worrisome sign for the upcoming fire season. Snow droughts like the one the West is experiencing can dry out soil, kill trees, and lessen stream flow: ideal conditions for a wildfire to grow. Meanwhile, the water supply in the Colorado River could drop even lower. States that rely on the river are already facing a political crisis as they attempt to renegotiate water rights; a drought would only up the ante.

Then there’s El Niño. Last week, the National Weather Service announced that there was more than a 60 percent chance of an El Niño event emerging in August or September. Various weather models suggest that this El Niño could be particularly strong. While we likely won’t know for sure until summer, “the fact that [all the models] are moving upwards is worth watching,” says Zeke Hausfather, a research scientist at Berkeley Earth.

El Niño is a natural cycle of climate variability, usually concentrated in the tropical Pacific, that pushes heat from the ocean into the atmosphere and towards the western coast of the US. El Niño years are typically warm—an average El Niño can increase yearly global temperatures by 1.2 C.

No one can predict for certain what impact, exactly, El Niño will have in the coming months. The phenomenon has a variety of effects on weather around the world. “It’s not always super consistent: Some areas get wetter, and some areas get drier,” says Hausfather. In the US, El Niño is generally associated with cooler and wetter conditions in the Southeast and Southwest with warmer conditions in western Canada and Alaska.

This could be potentially good news for some areas in the Southwest that, following a parched summer due to lack of snowpack, need more water. But, says Swain, an El Niño event could also increase the chances of dry thunderstorms in some areas—which up the chance for wildfires from lightning in already-dry terrain. During the last strong El Niño event in 2016, heavy rain triggered mudslides in some areas of drought-stricken California. Heavy storms in areas affected by both wildfires and drought have been linked to increased likelihood of mudslides.

“People talk about ‘climate chaos’—I don't love the term in the context of climate change, because we still have a very structured climate,” says Swain. “But a very strong El Niño event really does induce chaos. It induces patterns that are very different from typical historical norms.”

And there’s no denying that human-caused climate change is upping the ante for heat increases from natural events like El Niño.

“Obviously, any El Niño event that happens is happening on top of human-caused climate change,” Hausfather says. “We’ve warmed the planet 1.4 degrees [Celsius]. So you’re going to have a much bigger impact from heat, for example, if you start at that level versus 150 years ago.”