A winter storm placed around 49 million people under winter weather alerts over the weekend. It caused whiteout conditions on highways across the Midwest, between cities like St. Louis and Chicago.

Public agencies across Indiana are warning drivers about hazardous road conditions as winter weather creates slick roads and numerous crashes throughout the state.

Now is a good time to brush up on the essential winter weather terms and definitions so you can react quickly, plan ahead and stay out of danger.

The National Weather Serivce is predicting the first major snow storm could hit the western Upper Peninsula during the Thanksgiving Holiday weekend. The NWS office in Marquette has issued a winter storm warning for Northern Houghton,