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

A lake-effect storm continued to blanket parts of the Great Lakes region with snow on Saturday, closing highways on one of the biggest travel weekends of the year and prompting Gov. Kathy Hochul of New York to declare a state of emergency on Friday in 11 counties.