Flood Watch in effect for Iowa River at Wapello and Oakville through Friday night

The National Weather Service in Quad Cities has issued a Flood Watch for the Iowa River at Wapello and at Oakville, both in Louisa County, Iowa — running from Tuesday morning through late Friday night.

As of 8:00 PM CDT Saturday, the Iowa River at Wapello stood at 15.9 feet. Flood stage there is 21.0 feet, and forecasters say that threshold could be reached as early as late Tuesday morning, according to weather.gov.

Separately, a flash flood threat was already unfolding early Sunday morning. At 5:45 AM CDT, Doppler radar showed thunderstorms dropping heavy rain across a broad area of eastern Iowa and northwest Illinois, with 1 to 2.5 inches already on the ground and an additional 0.5 to 1 inch possible, according to meteoblue. Flash flooding was described as ongoing or expected to begin shortly.

The flash flood danger spans a wide swath of communities. Locations expected to experience flash flooding include Dubuque, Asbury, Dyersville, Monticello, Bellevue, Cascade, Epworth, East Dubuque, Farley, Peosta, Earlville, Hopkinton, New Vienna, Colesburg, Worthington, Holy Cross, La Motte, Luxemburg, and Rickardsville, according to meteoblue.

The broader Flood Watch for excessive rainfall covered portions of Illinois — including Bureau, Carroll, Henry, Jo Daviess, Mercer, Putnam, Rock Island, Stephenson, and Whiteside counties — and Iowa counties including Benton, Buchanan, Cedar, Clinton, Delaware, Dubuque, Iowa, Jackson, Johnson, Jones, Keokuk, Linn, Louisa, Muscatine, Scott, and Washington. That watch was in effect until 1 PM CDT Sunday afternoon.

Storms in that watch area were capable of rainfall rates between 1 and 2 inches per hour, with totals of 1 to 3 inches likely in the hardest-hit areas and the potential for localized amounts of 4 to 5 inches, according to meteoblue.

Impacts include flash flooding of small creeks and streams, urban areas, highways, streets, underpasses, and other low-lying or poor-drainage locations. In hilly terrain, low-water crossings are especially dangerous — authorities warn drivers not to attempt crossing flooded roads and to find alternate routes.

Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles.— NWS / meteoblue alert

Residents are urged to be especially cautious at night, when flood dangers are harder to recognize. Anyone who observes flooding is asked to report it to local emergency services or law enforcement and request that the information be passed to the National Weather Service.

The river-specific Flood Watch for the Iowa River at Wapello and Oakville runs well beyond the immediate storm threat — through late Friday night — reflecting the slower pace at which river levels rise and fall after heavy rainfall soaks the upstream watershed. Residents in Louisa County should monitor forecasts through the week as runoff continues to drain into the Iowa River.

Why it matters — Residents in Louisa County and across eastern Iowa and northwest Illinois face both an immediate flash flood danger and a slower-building river flood that could persist through the end of the week.

Reported by weather.gov, meteoblue.com