More than 4 million people across five states were under winter storm alerts on Sunday as heavy lake-effect snow continued to bury the Great Lakes region, prompting emergency declarations and the deployment of National Guard troops to rescue stranded motorists.

Parts of New York were hit by a lake-effect snowstorm on Friday, causing white-out conditions for drivers in one of the busiest driving weeks of the year. Thanksgiving week brought cold temperatures to much of the United States,