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 snow storm led to an emergency declaration in parts of New York and a disaster declaration in Pennsylvania, with officials warning of dangerous conditions for Thanksgiving travelers returning home. A blast of Arctic air brought bitter temperatures of ...

The lake-effect snowstorm has disrupted holiday travel across the region. Some areas could get up to six feet of snow by Tuesday.