The National Weather Service issued flood advisories Sunday afternoon for McHenry, Lake, DuPage and Cook counties as thunderstorms dumped rain at rates approaching 1.5 inches per hour. The advisories, which remain in effect until 4 p.m., warn residents of the potential for rapid flooding in low‑lying areas and near streams.
Two distinct waves of strong to severe thunderstorms swept across the Chicago region on Sunday, delivering intense, short‑duration rainfall. Meteorologists noted that the heaviest bursts produced nearly 1.5 inches of rain in a single hour, a rate capable of overwhelming drainage systems and causing water levels to rise quickly.
County emergency management officials in McHenry, Lake, DuPage and Cook counties confirmed that the advisories were coordinated with the National Weather Service to alert the public to the heightened risk. They emphasized that the flood advisories are precautionary, aimed at reducing the chance of damage and ensuring safety as the storms move eastward.
Residents in the affected suburbs have been urged to monitor local weather updates and avoid traveling through known flood‑prone zones. The National Weather Service will continue to track rainfall totals and issue further guidance if conditions worsen before the advisories expire at 4 p.m.
The combination of rapid, heavy rain and saturated soils from prior showers contributed to the swift development of localized flooding concerns. While no major incidents have been reported so far, the advisories reflect the potential for water to accumulate on roadways, in basements and near riverbanks as the storm system progresses.
Authorities advise drivers to exercise caution, allow extra travel time, and seek higher ground if water begins to rise. The public is also reminded to stay informed through official channels as the situation develops throughout the afternoon.