The National Weather Service rarely reaches for the word "catastrophic." It did this week — twice.
- The remnants of Hurricane Polo are merging with a Pacific low to form a "hybrid storm" dumping days of heavy rain across the U.S. Southwest and Plains.
- NWS flood watches now cover 10 states — Arizona, Utah, New Mexico, Colorado, Texas, Oklahoma, Kansas, Nebraska, Iowa and Missouri — with some areas forecast to see 5 to 8 inches.
- The NWS warned of "locally catastrophic flash flooding" from Texas to Kansas, and severe thunderstorms with a tornado risk are possible across the southern Plains.
- Polo made landfall in Mexico on Tuesday as a Category 2 hurricane with 110 mph winds; no deaths have been reported.
- Flash flooding is already happening: the Rio Grande swelled past its banks in New Mexico, forcing water rescues along I-25.
A hurricane died in Mexico. Its water is drowning the American Southwest.
Polo struck Baja California Sur on Tuesday as a Category 2 hurricane with 110 mph winds near Las Barrancas, about 80 miles north of Cabo San Lazaro. It pummeled the peninsula's west coast, flooded streets, scattered fallen trees, and pushed roughly 700 people into shelters. Then it crossed the Gulf of California, made a second landfall in Sonora, and died as a tropical cyclone.
But a hurricane's water outlives the hurricane. Polo's tropical moisture is surging north and colliding with a Pacific low, forming what USA Today calls a "hybrid storm" — a sprawling shield of rain the Weather Prediction Center says will hammer the central U.S. for five straight days.
NOAA satellite imagery showing Hurricane Polo as its tropical moisture began surging toward the U.S. Southwest. Photo: NOAA / Wikimedia Commons
Ten states, millions of people, five days of rain
The numbers tell the story. The NWS has issued flood watches across parts of 10 states: Arizona, Utah, New Mexico, Colorado, Texas, Oklahoma, Kansas, Nebraska, Iowa and Missouri. Flash flood warnings were already in effect Tuesday afternoon across southern Arizona and New Mexico, where the Weather Service reported "up to 3 inches of rain have fallen" with "flash flooding ongoing or expected to begin shortly."
Three of the next five days carry a moderate risk — level 3 of 4 — for excessive rainfall, meaning serious flash flooding is likely. By the weekend, parts of the Great Plains and Midwest could see 4 to 8 inches total, with some Texas spots facing 5 to 6 inches or more. Dallas and Phoenix are both inside the watch zone.
And the ground can't take it. Baked-dry soil in the drought-impacted Southwest can't absorb tropical downpours fast enough — exactly how flash floods explode out of nowhere, especially near burn scars, low-water crossings and complex terrain.
The tornado risk nobody asked for
Rain isn't the only threat. The Storm Prediction Center flags a slight risk — level 2 of 5 — for severe thunderstorms Wednesday across Texas and Colorado, with tornado warnings issued for parts of Oklahoma, Nebraska and Texas. Damaging winds and large hail could ride along with the worst storms: a cruel double act of water from below and twisting wind from above.
Three tropical systems lined up in the eastern Pacific on Sept. 25 — the moisture engine behind this week's "hybrid" U.S. storm. Photo: NOAA / Wikimedia Commons
It's already flooding
This isn't future-tense. On Tuesday, flash flooding overtook I-25 near Hatch, New Mexico, as the Rio Grande swelled past its banks and firefighters performed water rescues. Heavy rain has already flooded parts of Utah and Nevada, per Weather Prediction Center forecaster Marc Chenard.
The threat then shifts east: possible flash flooding from central Texas to central Oklahoma into Thursday, with flash, urban and river flooding across eastern Nebraska and western Iowa mid-week. Heavy bands could stretch from Arizona to Chicago.
The wider picture
The setup is ominous. The central U.S. already endured a summer of deadly flooding, evacuations and prolonged power outages — and now an El Niño-charged Pacific is feeding deluges from Mexico and Hawaii into the mainland. Even a "predecessor rain event" — heavy rain falling hundreds of miles ahead of the cyclone — primed the Southwest before Polo's remnants arrived.
If you live anywhere from Phoenix to Dallas to Omaha: watch the sky, stay off flooded roads, and take flood warnings personally. Six states face potentially life-threatening flooding, and this slow mover isn't leaving for days.