People are urged not to burn debris or have outdoor fires and be cautious with materials that can spark a fire.

At least 9 million people in the nation's upper Midwest region are under red flag warnings on Monday, including residents of Minnesota, where a wildfire was already burning out of control in the largest national forest east of the Mississippi River.

MADISON (WKBT) -- The DNR and NWS have issued Red Flag warnings for 21 Wisconsin counties. The warnings are in effect from noon to 9:00 p.m. Monday in the following counties: A Red Flag warning means conditions are especially dangerous for wildland fires. Burning is prohibited in areas where the DNR has burn restriction authority.