The first big snow of the season threatened to bury towns in New York along lakes Erie and Ontario during a hectic holiday travel and shopping weekend, while winter storm conditions could persist into next week and cause hazards in the Great Lakes, Plains and Midwest regions.

An Arctic outbreak of cold air will expand south and east and bring “dangerously cold wind chills” into the Northern Plains and Upper Midwest, the National Weather Service said Saturday, while heavy lake-effect snow could make travel “very difficult to impossible” into next week.