Moderate To Major Flooding Forecast As Northern Illinois Rivers Continue To Climb

A Flood Warning remains in effect through early Saturday morning for portions of northern Illinois after thunderstorms dropped up to 2 inches of rain, causing widespread runoff and rising river levels across the region.

The National Weather Service Chicago said the warning is in effect until 8 a.m. Saturday for parts of Lake and McHenry counties, replacing an earlier flash flood warning following overnight storms, according to the National Weather Service.

As of 2 a.m. Saturday, radar and rain gauge data indicated heavy rainfall from thunderstorms was still impacting the region. Flooding is either already occurring or expected to begin shortly, with some areas already seeing elevated water levels in streams and creeks, weather officials said.

Communities potentially affected include Waukegan, Buffalo Grove, Crystal Lake, Gurnee, Mundelein, Algonquin, Lake in the Hills, McHenry, Woodstock, Zion and surrounding suburbs. Officials warned that roads and low-lying areas may become inundated, especially where drainage systems are overwhelmed.

Authorities emphasized that drivers should avoid flooded roadways, noting that most flood-related deaths occur in vehicles.

River flooding worsens along Des Plaines River

Separate river flood warnings remain in effect for the Des Plaines River, where conditions have worsened in multiple locations.

At Russell, moderate flooding is underway with water levels rising quickly following recent rainfall. Officials reported the river jumped from 8.7 feet to over 9 feet in a short period, with a crest expected just above 9 feet before a gradual decline, according to the National Weather Service.

Farther downstream near Lincolnshire, conditions have escalated to major flooding. The river is forecast to crest near 15.5 feet late Saturday, with impacts including flooding of buildings along roads such as Half-Day Road, Milwaukee Avenue and Deerfield Road, as well as inundation of trails and low-lying forest preserve areas.

Officials said flooding could continue into next week before waters fully recede.

Fox River also under flood warning

Moderate flooding continues along the Fox River, including areas near Algonquin, Elgin, East Dundee and St. Charles. Water levels are expected to crest near 11.5 to 12 feet late in the week, with multiple residential areas, roads, and park trails threatened along the river corridor, according to the National Weather Service

Flood stage thresholds have already been exceeded in several monitoring locations, and additional rainfall could extend or worsen flooding impacts.

Officials urge caution

The National Weather Service reiterated that flood warnings mean flooding is either imminent or already occurring.

Residents near rivers, creeks, and flood-prone roads are urged to take immediate precautions to protect life and property.

“Turn around, don’t drown,” officials cautioned, emphasizing heightened danger during nighttime hours when flooded roads are harder to see.

Additional updates are expected as river levels continue to be monitored through the weekend.