CAN A HISTORIC EL NIÑO BREAK THE DROUGHT?
By Matt Makens Atmospheric Scientist
After years of drought growth across much of the country, there are recent signs of reversing that trend. One of the strongest El Niño events on record has developed in the Pacific Ocean, and it will bring much-needed moisture to some of the nation’ s driest areas this winter and spring.
But there is a catch. The drought we are dealing with is widespread, and in some places has been building for years. We are dealing with substantial moisture deficits, so even a very wet winter might not be enough to erase drought from the southern or western U. S. Just how bad is the drought? By October, approximately 55 % of the lower 48 states were experiencing drought. Across Oklahoma and Texas, that number was even higher, at 85 %. More than half of those two states were dealing with severe drought or worse.
Drought is not simply a matter of how much rain has fallen in recent weeks. There is a big difference between dry topsoil versus a shortage of water that has developed over several years. A few good storms can improve pastures and help crops in the short term, but restoring groundwater, reservoirs, and deeper soil moisture takes a lot longer.
To understand that longer-term problem, I looked at drought records going back to 1895. By late summer, some areas of the West and Northern Rockies had drought readings near the worst levels this particular dataset( Palmer Hydrologic Drought Index) can have, and it will take more than one or two wet seasons to restore the water availability needed. Why El Niño matters El Niño develops when ocean temperatures across the tropical Pacific become warmer than normal. Those warmer waters influence the global atmosphere, changing where storms develop and how they move across North America.
Typically, El Niño strengthens the southern storm track during winter. That favors wetter conditions from California and the Southwest through Texas, Oklahoma, and parts of the Southeast. Meanwhile, the northern United States often experiences a warmer winter with infrequent moisture.
However, one point deserves attention: a stronger El Niño does not automatically mean more moisture – there are offsetting factors that can alter even the strongest of patterns. To get a sense of what is possible, I compared past El Niño winters, including the strongest events, and found considerable differences where the heaviest precipitation occurred in each( my YouTube channel is full of videos sorting out these comparisons). Some brought substantial drought relief to the Plains. Other El Niños sent much of their moisture farther west or east. El Niño changes the odds. It does not guarantee the outcome. Can one winter undo years of drought? This is where historical comparisons become important. I took a deeper dive into how drought conditions changed during previous El Niño events.
Typically, there was improvement across the southern United States, particularly the Southwest and Southern Plains. Some improvements began within a few months, but the more substantial drought recovery generally took much longer.
I took this a step farther and wanted to see what would happen if each region received its highest precipitation recorded from those previous El Niños. Under this theoretical scenario, drought across much of the country could recover significantly, but even if our current event delivered the
18 NOVEMBER 2026 www. NCBA. org