Deep freeze grips Upper Midwest; more bitter cold to come

  • A runner and his dog brave frigid conditions while making their way east across the Stone Arch Bridge, Thursday, Jan. 24, 2019, in Minneapolis. The National Weather Service issued a wind child advisory overnight Thursday for Wisconsin, Minnesota, the Dakotas and several other states. (David Joles/Star Tribune via AP)

MINNEAPOLIS — An arctic wave has wrapped the Upper Midwest in numbing cold. But the worst may be yet to come.