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.

The Lake-effect snowstorm that severely affected parts of Buffalo, New York, Pennsylvania, and Michigan this Thanksgiving weekend has prompted officials to caution travelers returning home after the T

The snowfall was heaviest along Interstate 90, the National Weather Service said, which hugs Lake Erie from Buffalo, New York, and on to Cleveland.