Despite the declaration third warmest year on record. The year 2025 was relatively silent in terms of climate disasters in the US. No major hurricanes made landfall, while in total number of acres the amount burned last year from wildfires – a way of measuring the intensity of the fire season – fell below the 10-year average.
But starting this week, the West is experiencing what appears to be a record heatwave, and forecast models predict a robust El Niño event is likely to occur later this year. These two unrelated events could set the stage for a long period of unpredictable and extreme weather that will last well into next year, exacerbating the effects of an increasingly hotter climate caused by human activity.
First of all, it’s balmy. Starting this week and heading into next, a massive ridge of high pressure will bring record temperatures to the American West. National Weather Service predicts that multi-state temperature records will be broken in dozens of locations, reaching as far east as Missouri and Tennessee. The NWS issued heat warnings for parts of California, Arizona and Nevada, as well as wildfire warnings for parts of Wyoming, Nebraska, South Dakota and Colorado.
“This will be the strongest single ridge we have seen in any month outside of summer,” says Daniel Swain, a climate scientist at the University of California Agriculture and Natural Resources.
The other unusual thing about this heat wave, Swain says, is how long it will last. “It’s not a day or two of extreme heat,” he says. “We have been seeing record highs every day for a week in some of these places and we expect to see them every day for at least seven to 10 days.” The later end of March will be much more intense, and temperatures in some places will break the records of April and May. “There aren’t many weather patterns that can result in 85- to 90-degree temperatures in San Francisco, Salt Lake City and Denver in the same week.”
This tardy winter heatwave is on top of an already balmy winter across the West – with earnest consequences for summer. A month ago, snowpack levels were at record lows in many states thanks to higher than average temperatures. Snowpack levels in many Western states continue to remain below 50 percent of average, according to data provided by the Department of Agriculture. Snowpack is a key natural reservoir for rivers in the West; 60 to 70 percent of the region’s water supply in many areas comes from snowmelt. Low snowpack is a bad sign for already stressed rivers like the Colorado, which provide water for 40 million people in seven states.
The ongoing heat wave, Swain says, will likely make conditions even worse. “April 1 is usually when snowpack reaches its peak, at least in the past,” he says. Even if temperatures frosty down into summer, low snowpack is also a troubling sign of the upcoming fire season. Snow droughts like the one the West is experiencing can desiccated out soil, kill trees and reduce streamflow: ideal conditions for wildfires to thrive. Meanwhile, the Colorado River’s water supply could decline even further. States that depend on the river are already facing a political crisis as they try to renegotiate water rights; drought would only raise the stakes.
Then there’s El Niño. Last week, the National Weather Service announced that there is more than a 60 percent chance of an El Niño event occurring in August or September. Various weather models suggest that El Niño may be particularly robust. While we probably won’t know for sure until the summer, “the fact is [all the models] they’re going up,” says Zeke Hausfather, a scientist at Berkeley Earth.