A massive winter storm will sweep across the United States this weekend, affecting more than 160 million people with snow, sleet, freezing rain, and extreme cold. The National Weather Service (NWS) warned the storm will cause "extremely dangerous" conditions as it moves from the High Plains and Rockies eastward. Winter storm warnings affect 58 million people. Heavy snow and ice could damage roads, power lines, and disrupt transport. Some areas in the Southern Plains, Ohio Valley, Mid-Atlantic, and Northeast could see snowfall totals above 12 inches. Freezing rain may coat trees and power lines, raising risks of power outages. Meteorologist Richard Bann said, "Freezing rain and ice make travel difficult, if not impossible." The storm timeline: - Friday: Starts in Southern Rockies with scattered snow in Colorado and New Mexico, spreading to Kansas, Oklahoma, and Texas Panhandle. - Saturday: Moves into Texas overnight, then Arkansas, Tennessee, Midwest, and parts of the Southeast, with snow north and sleet/freezing rain south. - Sunday: Hits the Mid-Atlantic and New England with wintry weather. - Monday: Snow eases in Northeast while bitter cold moves in from Southern Plains through New England. Eleven states including Alabama, Arkansas, Georgia, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, Texas, and Virginia have declared states of emergency. The National Weather Service in Norman, Oklahoma, cautioned, "Travel is going to become more and more treacherous starting late Friday afternoon and lasting through the rest of the weekend." Flight cancellations have reached about 1,300 across the US, with more expected. Delta canceled flights in several states. Roads are also hazardous. Dallas and Louisiana transportation agencies are preparing by salting roads in advance. Commuter rail systems like New Jersey Transit, Metro-North Railroad, and Long Island Rail Road will provide real-time updates. Amtrak warns of possible service changes nationwide depending on storm conditions. Power outages from ice accumulation are a major concern. Mr. Bann added snow in areas lacking equipment could stay icy for long, making travel even more dangerous. Emergency officials urge people to prepare for power cuts, travel troubles, and freezing cold. Grocery stores are seeing rushes as residents stock up before the storm hits.