The National Weather Service issued a Dense Fog Advisory overnight for areas including Hudson and Stillwater. The advisory is in effect until 10 a.m. Saturday.
"Dense fog developed over much of west central Wisconsin into east central Minnesota" the NWS statement said. "Visibility was near zero in some locations."
Driving will be difficult in some areas due to reduced visibility and slick bridge decks and ramps. Frost will also make sidewalks slippery.
If you are driving, the NWS advises you slow down, use your headlights and leave plenty of distance ahead of you.
These are the Minnesota and Wisconsin counties included in the Dense Fog Advisory: Stearns, Sherburne, Isanti, Chisago, Meeker, Wright, Hennepin, Anoka, Ramsey, Washington, McLeod, Carver, Scott, Dakota, Polk, Barron, Rusk, St. Croix, Pierce, Dunn, Pepin, Chippewa and Eau Claire.