A lake-effect storm devastated parts of the Great Lakes region Friday evening, shutting down highways on one of the biggest travel days of the year in the United States.

Communities on the shores of Lake Erie and Lake Ontario – in New York state, Pennsylvania and Ohio – were covered in snow, and the National Weather Service (NWS) urged residents to stay indoors.

Nearly 30 inches of snow has already fallen in some spots along Lake Erie, the NWS said Saturday, and up to 6 feet of snow is expected to accumulate by Monday.

As the snow piled up, an arctic blast ripped through the northern Plains and Midwest, pushing freezing air across the region.

Double-digit temperature drops were expected from Minnesota to Texas as cold air swept across the record-warm Great Lakes, bringing the season’s first lake-effect snowfall.

Lake effect snow is common in this region of the United States and Canada in the winter, when very cold air flows over the relatively warm waters of the lakes.

These types of storms can produce large, although fairly localized, snowfalls.

“Roads, particularly bridges and overpasses, are likely to become slick and dangerous,” the NWS said in its forecast for Saturday morning, adding that visibility could drop below a quarter mile due to falling and drifting snow. The NWS warned that whiteout conditions are expected in areas across the region.

New York Governor Kathy Hochul declared a state of emergency in 11 of New York’s 62 counties due to the storm. She told Spectrum News on Friday that state officials are “prepared for the worst.”

“We are so used to this type of storm,” Hochul said. “We don’t love it, but it’s part of who we are as New Yorkers, especially in Western New York and the North Country.”

“There will be local areas that will be paralyzed by the lake snow and some highways will also be severely affected,” the National Weather Service in New York said.

Road closures in the region included a section of Interstate 90 in Pennsylvania, disrupting travelers between Cleveland, Ohio and Buffalo, New York on one of the busiest travel weekends of the year following the Thanksgiving holiday on Thursday.

According to AAA, the automobile association, about 80 million people will travel for Thanksgiving this year.