WINDSOR TOWNSHIP, Mich. (AP) — Michigan Gov. Gretchen Whitmer is closing state government for the third day this week due to winter weather, saying the step is needed to keep people safe.

Essential employees are continuing to work.

Whitmer — who announced Wednesday that state offices will remain closed Thursday — visited the State Emergency Operations Center near Lansing, thanking workers after getting a briefing. The National Weather Service says the extreme cold will last into Thursday. Wind chill factors of minus 40 degrees (negative 40 degree Celsius) can quickly lead to frostbite.

Free bus rides are being offered in the Detroit area. Mail delivery is suspended. Universities and schools are closed.

Amid snow, winter storm warnings are in effect. Dozens of flights are canceled at the Gerald R. Ford International Airport in Grand Rapids.