Elmhurst and Villa Park residents along Salt Creek face a rising flood risk as heavy rain pounds northern Illinois through Thursday night.

The National Weather Service expects 1.5 to 3 inches of rain across the Chicago area by Thursday night, Oct. 1. Repeated downpours raise the threat of flooding in low-lying and poor-drainage areas, Shaw Local reported Wednesday, Sept. 30.

NWS meteorologist Gino Izzi told the Chicago Tribune that minor flooding is possible along some rivers, though no major flooding is expected. The flood risk is "elevated" on Thursday, and a hazardous weather outlook advisory covers Cook County and northeast Illinois.

Thunderstorms are also possible Wednesday night across the region, according to the NWS.

What's at risk locally

The NWS flagged the DuPage, Des Plaines, Rock, Fox and Illinois rivers for rising water levels. Residents in Elmhurst, Villa Park and Oakbrook Terrace who live near those waterways should monitor conditions and prepare for potential flooding, the agency said.

In Elmhurst, Salt Creek is the primary concern. When the creek reaches flood stage, water can spread across roadways and structures up to eight blocks out, according to the NOAA National Water Prediction Service.

Route 83 between North Avenue and St. Charles Road has a history of flooding in heavy rain. During a July 28 storm that dropped 2.41 inches on Elmhurst and up to 2.50 inches on Villa Park, Route 83 was closed in both directions at that stretch.

Flood control facilities

DuPage County operates several flood control facilities along Salt Creek. The Elmhurst Quarry Flood Control Facility, an 8,300 acre-foot reservoir south of North Avenue on Route 83, diverts excess Salt Creek water through a 400-foot tunnel when levels near flood stage, according to DuPage County Stormwater Management.

Eldridge Park Reservoir in southwest Elmhurst holds nearly 40 million gallons of flood protection for the Salt Creek watershed. The Wood Dale-Itasca Flood Control Facility protects downstream communities including Villa Park and Elmhurst.

What's driving the rain

The steady soaking is fueled by remnant tropical moisture from Hurricane Polo. The storm made landfall in Mexico's Baja California Sur on Monday, Sept. 28, as a Category 1 hurricane before dissipating Tuesday. Its warm, moist air is pushing as far north as Wisconsin, according to Izzi.

"Certainly, the drier-than-normal conditions through the first few weeks of October don't mean it's not going to rain at all; it just means on the whole, precipitation will tend to end up below average," Izzi told the Tribune about the longer-range outlook. Two abnormally dry weeks are expected to follow the storm.

What residents should do

The Villa Park Police Department has standing guidance for residents who encounter flooding. In an Aug. 1 message, the department urged residents to call 911 to report flooded streets, downed trees or other hazards so dispatchers can alert Public Works.

Residents can monitor Salt Creek water levels at the NOAA gauge page for Elmhurst and check NWS Chicago for updated flood advisories.