(Reuters) - A series of winter storms, packing heavy snow and gusty winds, grounded flights and knocked out power for tens of thousands of people in the Pacific Northwest, where forecasters predicted more snow could fall on Sunday.

Seattle residents woke on Saturday to the rare sight of their city covered in white as the National Weather Service kept winter storm warnings in effect for much of the region.

Washington Governor Jay Inslee declared a state of emergency on Friday as the first powerful winter storm approached, warning it could be unlike any Seattle had seen in many years.

“I encourage everyone to stay off the roads if possible,” Inslee said in a statement.

As of lunchtime Saturday, nearly 50,000 customers in the Puget Sound region were still without power after snow and winds on Friday cut the lights and sent crews scrambling to restore power overnight, Puget Sound Energy reported.

A record 6.4 inches (16 cm) of snow piled up at the Seattle-Tacoma International airport on Friday, the biggest accumulation since 2014, the National Weather Service said.

More than 225 flights were canceled at the airport on Saturday, according to the flight tracking website FlightAware.com.

The flakes stopped falling in Seattle on Saturday, but the weather service predicted snow could start again late on Sunday afternoon, with another 2 to 4 inches (5 cm to 10 cm) of snow possible by Monday morning.