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.”