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A late-season monsoon surge is pushing storms across the Wasatch Front on Wednesday, Sept. 16, raising the risk of localized flooding in Cottonwood Heights and Holladay.
The Storm Prediction Center placed parts of the Wasatch Front under a Marginal risk for severe weather, a Level 1 of 5 designation, for Wednesday afternoon, ABC4 reported. Gusty winds and large hail are possible with any storms that develop. Slot canyons, dry washes and small streams could experience flash flooding.
The National Weather Service forecast for Cottonwood Heights, updated at 12:45 p.m. Wednesday, called for a 30 percent chance of showers and thunderstorms after midnight, with a low around 61 degrees. Thursday brings a 50 percent chance of showers and thunderstorms, mainly before noon, with a high near 85.
The broader Northern Wasatch Front zone forecast is wetter. Thursday's chance of precipitation climbs to 70 percent, and Friday's reaches 80 percent, with highs dropping into the upper 70s before drier air returns for the weekend.
Why it matters locally
Big Cottonwood Canyon and Little Cottonwood Canyon empty directly into Cottonwood Heights and Holladay neighborhoods. That geography concentrates flood risk at canyon mouths when storms develop upstream. Runoff from storms miles away can create dangerous conditions at lower elevations with little warning.
The area's stormwater infrastructure remains a work in progress. After a powerful Aug. 14 storm flooded a Scottish Drive home for the third time, displacing the Condas family, Cottonwood Heights Mayor Gay Lynn Bennion told FOX 13 on Aug. 15 that the city's drainage system has not caught up with improvements elsewhere.
"We're still updating that system … It's going to take years to do and more funds to do it sooner would be prudent," Bennion said at the time.
The city instituted a stormwater fee in 2021 to fund upgrades, but Bennion said in August that more funding to accelerate the work would be prudent.
What to watch for
No Flood Watch or Flash Flood Warning was active for the Cottonwood Heights and Holladay area as of Wednesday afternoon. Conditions can change quickly. A Flood Watch means conditions favor flooding. A Flash Flood Warning means flooding is imminent or occurring and residents should move to higher ground immediately.
ABC4 meteorologist Cedric Haynes warned that low-lying areas are not safe during active storms and that drivers should never cross floodwaters.
Cottonwood Heights residents can sign up for city emergency alerts at the city's website. Salt Lake County also offers UPD Canyon Alerts through updsl.org and VECC Reverse 9-1-1 alerts through Smart911.
