GURNEE, Ill. — Illinois officials said Friday some 6,800 buildings have been affected by “unprecedented” flooding north of Chicago, and the damage is expected to worsen this weekend as water flows down rivers into the state from Wisconsin.

“Folks think, ‘Well, it’s not raining anymore. Things are just fine, they’re getting better.’ Well, they’re not,” Illinois Gov. Bruce Rauner said following a tour Friday of the area. “This is dangerous, and the danger has not gone away.”

The National Weather Service says the Des Plaines River and Fox River could crest on Saturday. Rauner said that could prompt local officials to evacuate some neighborhoods and communities.

Heavy rainfall that hit the Midwest on Wednesday knocked out power to thousands and closed roadways. Power outages caused by flooding forced the evacuation Wednesday of Lake Forest Hospital in suburban Chicago. Power was restored that night, but Northwestern Medicine says the hospital remained closed Friday while damaged infrastructure is restored.

Wisconsin Gov. Scott Walker declared a state of emergency in Kenosha, Racine and Walworth counties on Thursday, and the National Guard was helping local officials in that state go door-to-door to check on people.

In Illinois, Lake County issued a disaster declaration, and late Friday afternoon Rauner’s office issued a state disaster proclamation for Lake, McHenry and Kane.

Rauner also directed Illinois Emergency Management Agency (IEMA) Director James K. Joseph to activate the State Emergency Operations Center (SEOC) as needed over the weekend and into next week to coordinate any requests for assistance from flood-impacted communities.

Joseph said rivers could crest at record levels, and the agency is working with local officials in Lake, McHenry, Kane, Cook and parts of DuPage counties.

Of the roughly 6,800 buildings that have been affected, about 2,100 are submerged — many along the Chain O’Lakes, Lake County Board Chairman Aaron Lawlor said. Officials predict there could be 5,800 submerged structures before the waters recede, he said.

Lawlor said the flooding is expected to be worse than the damage in 2013, the last time the area was hit, because rains “came down right on top of us.”

“This is an unprecedented flood,” he said.

For updates, visit the state’s website at www.ready.illinois.gov.