An El Niño winter is coming to Oregon, and it could be one of the strongest on record. If you have heard that El Niño means a mild, dry winter in the Pacific Northwest, you may be wondering whether this is the year you can stop worrying about your basement or crawl space.
Here is the short answer: probably not. Forecasters do not agree on how much rain this El Niño winter will bring, and Oregon’s own state climatologist has said this one is likely to be warmer and wetter than usual. Your basement does not care about seasonal averages. It cares about how much water reaches the soil around your foundation, and how fast.
I am Dylan with Better Basements & Waterproofing. We keep basements and crawl spaces dry throughout Portland, Eugene, and Vancouver. Here are four honest truths about what this El Niño does and does not change for your home.
What Is an El Niño Winter?
El Niño is a climate pattern that starts with warmer-than-usual ocean water in the central and eastern tropical Pacific. That warm water shifts weather patterns across North America, including the storm tracks that bring rain to the West Coast.
This year’s event is unusually strong. NOAA has put the chance of a very strong El Niño during fall and winter 2026-27 at greater than 90 percent. Oregon has lived through very strong events before, in 1982-83, 1997-98, and 2015-16.
Truth 1: “El Niño Means a Dry Winter” Is Only Half the Story
The usual rule of thumb says El Niño brings the Pacific Northwest warmer, drier weather. That holds true in many El Niño years.
But very strong events do not always follow the usual pattern, and this year’s forecasts reflect that. In a September interview with OPB, Oregon State Climatologist Larry O’Neill said this El Niño is likely to bring Oregon warmer weather and more rain, with a higher risk of floods and landslide.
The honest takeaway: nobody can promise you a dry El Niño winter. Plan for a normal rainy season or a wetter one.
Truth 2: A Warmer Winter Puts More Rain Into Your Soil
When winter runs warm, more of the season’s precipitation falls as rain instead of snow. Rain does not wait in the mountains. It soaks into the ground around your foundation right away.
In the Portland area, clay-heavy soil holds that water. When the soil stays saturated, water presses against your foundation walls and floor. That force is called hydrostatic pressure, and it pushes water through cracks, through the joint where the wall meets the floor, and through porous concrete.
Read our guide on how water gets into your crawl space or basement to see every entry point water uses.
Truth 3: One Atmospheric River Is All It Takes
Seasonal averages blend dry weeks and big storms together. Your basement only has to fail once.
Atmospheric rivers are long plumes of moisture from the tropical Pacific, and they deliver many of the West Coast’s heaviest rainstorms. NOAA’s Climate.gov reports that in El Niño winters from 1992 to 2020, the number of days with atmospheric rivers was above average along the U.S. West Coast. Scientists are still studying how strongly El Niño drives these storms, so treat that as a tendency, not a forecast.
Either way, a quiet month followed by one intense storm can overwhelm a sump pump that has sat idle since spring, or a drainage system that was already borderline. Read how to test a sump pump before the next big system arrives.
Truth 4: Your Basement’s Weak Points Do Not Change With the Forecast
A crack that leaked last winter is still there. A downspout that dumps water at the foundation still does. A sump pump that is nine years old does not get younger because the forecast changed.
What changes the outcome is what you fix before the storms arrive:
Test your sump pump and confirm water actually exits the discharge line outside.
Clear your gutters and extend downspouts away from the foundation. Read our guide on gutters and downspouts in basement waterproofing.
Look for white mineral deposits, water stains, or musty smells that show where water has entered before. Read our guide on efflorescence on basement walls.
Check your crawl space for standing water or a torn liner. Read our guide on standing water under your house.
Get any actively leaking cracks evaluated before the peak of the rainy season.
What We Tell Homeowners This Fall
We are not weather forecasters, and we will not tell you that this winter is going to flood your basement. Nobody knows that yet.
What we can tell you is whether your home has a water problem right now, what is causing it, and whether it actually needs work. Sometimes the answer is gutters and grading. Sometimes it is a drainage system and sump pump. Sometimes it is nothing at all, and we will tell you that too.
Frequently Asked Questions About an El Niño Winter in Oregon
Will El Niño make this a dry winter in Portland?
Not necessarily. Typical El Niño winters lean warmer and drier in the Pacific Northwest, but Oregon’s state climatologist has said this very strong El Niño winter is likely to bring warmer weather and more rain.
Should I wait to see how wet this winter gets before fixing my basement?
If you already see signs of water entry, waiting usually means fixing the problem after the damage. If you see no signs, a quick pre-season check is enough.
Does El Niño bring more atmospheric rivers to Oregon?
NOAA data show above-average atmospheric river days along the U.S. West Coast in past El Niño winters, but scientists are still studying the connection, so it is not guaranteed.
What should I do before the first big storm?
Test your sump pump, clear gutters and downspouts, and look for signs of past water entry in your basement and crawl space.
Get Ready Before the Storms Arrive
Whatever this El Niño winter brings, the homes that stay dry are the ones that were checked before the rain. We will inspect your basement or crawl space, tell you exactly what we find, and recommend only the work you actually need.
Learn more about our basement waterproofing services
Schedule your free basement inspection here
Better Basements & Waterproofing serves Portland, Eugene, Vancouver, and surrounding communities in Oregon and Washington.
