A Winter Weather Advisory is in effect until 6 a.m. Thursday. Widespread freezing rain and drizzle are causing untreated roads, sidewalks, and driveways to become icy and slick. Ice accumulation of up to 0.

Millions of people from the Midwest to the Northeast are on alert as a developing winter storm is expected to bring a potentially crippling ice threat that could knock out power and lead to treacherous travel conditions across the region.