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.

The UK government recently unveiled its UK fusion strategy 2026, which includes £125m of funding to develop the artificial intelligence (AI) growth zone at Culham, Oxfordshire. This includes a £45m investment in “Sunrise”, the new fusion-dedicated supercomputer. 

One area in which Sunrise will be used is accelerating simulation, surrogates and design, where AI could simplify simulations or learn the behaviour of complex systems such as plasmas to speed up simulations that previously took weeks or months to run. 

It will also be used for data management, making the UK Atomic Energy Authority’s (UKAEA) fusion research and experimental data consistent, accessible and electronically readable. In addition, Sunrise offers the UKAEA – an executive non-departmental public body, sponsored by the Department for Energy Security and Net Zero – the ability to enhance experimental operations and control in real-time diagnostics, where AI can be trained to spot anomalies and flag issues. 

The role of high-performance computing (HPC) AI acceleration hardware within the government’s strategy for nuclear fusion is to prepare fusion data for AI applications to ensure that researchers from small and medium-sized enterprises (SMEs) and academic institutions can access data, supporting greater collaboration and engagement with industry partners.

The 6.76 exaflops Sunrise AI supercomputer involves a collaboration between AMD, DESNZ, the Department for Science, Innovation and Technology (DSIT), Dell Technologies, Intel, UKAEA, the University of Cambridge, and Weka, a data platform provider. 

Looking at its headline performance data, Rob Akers, UKAEA’s director for computing programmes, says: “It’s very challenging to define how powerful a piece of hardware like Sunrise is, because it depends on your metric for success.” 

Sunrise offers the full spectrum of floating point precisions, from 8-bit right the way up to 64-bit precision, but, as Akers points out, each one of those targets a different part of the problem. “The important thing for us is that we can’t forego 64-bit precision, because that’s what’s going to feed the artificial intelligence algorithms that we’ll be applying when using Sunrise as an engineering tool,” he says.

“Sunrise is not just a very powerful laptop – it is a very complex piece of machinery that we’ll be putting to the task of solving a very large set of complex problems”

Rob Akers, UKAEA

AI makes it possible to collapse high-fidelity models that need very high bit precision down into what UKAEA calls “surrogate” models, according to Akers, who adds that these surrogates can run on a workstation or a laptop in a tiny fraction of the time it would take the big solvers running on large supercomputers. 

“It’s almost like an instrument for discovery,” he adds. “Sunrise is not like a laptop. It’s not just a very powerful laptop – it is a very complex piece of machinery that we’ll be putting to the task of solving a very large set of complex problems.” 

One of the interesting numbers that pop up in the specification for Sunrise is the figure for 8-bit precision, especially given that 8-bit computing harks back to the era of the home computer some 50 years ago.

“The interesting thing is that 8-bit precision has become an incredibly powerful part of the computing landscape now because of large language models [LLMs],” says Akers. 

Running LLMs is in the UKAEA’s plans. “We are going to be doing work in that space, building very bespoke models that will ingest text document archives that have been collected over many, many decades, and turning that into useful information and knowledge,” he says.