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.

Forecasters warned that some areas would be “paralyzed” by the storm. Nearly three feet of snow had already accumulated in Perrysburg, N.Y., about 30 miles south of Buffalo.

A light dusting of snow began covering the Buffalo Bills' facility on Friday as the team completed its final practice of the week inside Highmark Stadium.