Continued rain, thunderstorms could raise Rock River to flooding level

DIXON – The severe thunderstorms and continued rain that hit the Sauk Valley over the weekend and through Monday mean the Rock River could flood this week, the National Weather Service office in Chicago warned.

A significant risk of thunderstorms – including possible tornadoes, damaging wind and hail – exists through 11 tonight in Ogle and Lee counties as “strong to severe thunderstorms are expected to move across the area this evening,” the National Weather Service said in a hazardous weather outlook issued Monday.

Scattered thunderstorms remain possible Tuesday afternoon, primarily near and south of Interstate 80.

The agency issued a flood watch for the Rock River at Dixon affecting Lee and Ogle counties and from Castle Rock State Park near Oregon downstream to Lee County line, including the Dixon gauge. The watch remains in effect through Thursday morning.

Data from the National Water Prediction Service showed water levels for the Rock River at Dixon was at 11.58 feet as of 2:30 a.m. Sunday, well below the 13 foot action stage.

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Ayla and Charlie Arellano wade through high waters Monday, July 15, 2024, below the Peoria Avenue bridge as river levels continue to raise as more rains hit the area. (Alex Paschal)

However, those levels increased to 14.26 feet by Monday and were projected to climb to 16.7 feet by Wednesday. Minor flooding occurs at 16 feet and moderate flooding at 18 feet.

When levels hit 15 feet, Page Drive at Page Park starts to flood, and by 15.5 feet, the picnic area is underwater. Backwater forces Sevenmile Branch to spill over near Forest Park Drive, north of Dixon, according to the flood watch.

Once levels reach 16 feet, North Canal Drive in Woodland Shores is under threat, and water starts creeping over West First Street in Dixon. Homes near Sherman Avenue and River Street in Dixon could also be in harm’s way.

The Rock River increased only 0.43 inches over the weekend, but heavy rainfall from continued thunderstorms over Monday night and Tuesday are projected to elevate the Rock River at Dixon’s flood stage. However, the weather is expected to start to clear up Wednesday with mostly sunny skies and highs in the 80s for the rest of the week.