Answer extracted from the Up First from NPR podcast — listen to the full episode below.
How does rainfall shift across the US when El Niño strikes?
During El Niño years, the southern half of the US typically experiences more intense rainfall that can trigger destructive flooding, while the northern half becomes drier—a pattern especially significant for regions like the Intermountain West that already face chronic drought and low snowfall.
A divided rainfall pattern with real consequences
El Niño doesn't distribute its effects evenly across the country. The Pacific Ocean's warming has a clear geographic divide: southern states absorb excess moisture and precipitation, creating conditions ripe for severe rain events and the flooding damage they bring. Meanwhile, northern regions see precipitation pull away entirely, deepening existing water stress.
For the Intermountain West, this dual impact creates a critical vulnerability. The region was already facing drought and low snowfall patterns, and El Niño's tendency to dry out the north compounds those water supply challenges during the very years when the phenomenon dominates global weather.
This year's El Niño is particularly powerful—modern El Niños are about 36 percent stronger than their pre-industrial counterparts, which means the rainfall extremes on both sides of the country will likely be more pronounced. The southern flood risk escalates, and northern drought intensity deepens.
A pattern layered on top of climate change
Understanding this rainfall split matters because it's happening within a warming climate. The planet is already 2.5 degrees Fahrenheit hotter from fossil fuel burning, which adds heat and destabilization to whatever rainfall pattern El Niño imposes. A naturally stronger El Niño amplifies an already warmer baseline, pushing both extremes—flooding in the south and drought stress in the north—further beyond historical norms.
See also
What are the projected temperature impacts of this Super El Niño in the United States?
This El Niño will raise temperatures globally, and since it occurs on top of climate change when the planet is already about 2.5 degrees Fahrenheit hotter from fossil fuel burning.
What makes the current El Niño a 'Super El Niño' and how strong is it?
Federal forecasters describe it as a very strong El Niño, with climate scientists noting modern El Niños are about 36 percent stronger than pre-industrial El Niños, making this one of the most powerful on record.
How does El Niño form and what are its planetary effects?
El Niño is a natural cycle where huge amounts of warm water accumulate in the Pacific Ocean around the equator, releasing substantial heat to the atmosphere with far-reaching ripple effects that change weather patterns from Germany to India.