Last-minute shoppers and holiday travelers slogged through freezing rain and ugly driving conditions across most of Maine on Saturday, and thousands of Mainers lost power as temperatures dropped in the evening.

Aside from a tractor-trailer crash early Saturday on the Maine Turnpike in Kittery and a head-on collision in Canaan, there were mostly only small weather-related incidents throughout the day.

With subfreezing temperatures expected overnight Saturday, forecasters were urging people to beware of icy roads – and to start getting ready for a white Christmas, with up to 8 inches of snow due to fall Monday in most parts of the state.

“If you’re looking to go over the river and through the woods, Sunday and Tuesday are the days to travel,” said Margaret Curtis, a meteorologist with the National Weather Service station in Gray.

Sunday’s weather is expected to be clear, with temperatures in the low 30s for much of the state, she said. Heavy snow is expected throughout southern Maine on Christmas, with 6 to 8 inches falling before early afternoon.

Despite the snow switching over to freezing rain on Saturday, weather-related problems were minimal, said local and state officials, who reported multiple small accidents due to weather conditions but no major accidents.

In the Kittery crash on the turnpike, the big rig was heading southbound at mile 1.5 near the New Hampshire border when it swerved to avoid hitting a car that had spun out, according to Maine State Police.

State police said Jason Ashburn, 22, of Andover, New Hampshire, was driving too fast for the conditions and lost control of his sedan just before 6 a.m. He struck the center median and then collided with the tractor-trailer, which was driven by Patrick Ebanks, 55, of Brockton, Massachusetts.

Ebanks had swerved to avoid the collision and ended up in the northbound lane under an overpass. Four lanes were temporarily shut down until the scene was cleared. Ashburn was transported to the hospital for minor injuries.

In Canaan, state police responded to a report at midafternoon of a head-on collision on Route 3. The driver of a sedan traveling toward Canaan crossed the centerline and crashed into a pickup truck, causing airbags to deploy. A trooper who went to the scene said one of the drivers suffered a minor head injury.

The speed limit was reduced to 45 mph for the entire length of the Maine Turnpike for most of the day.

At the airports, only a few flights were canceled due to weather. American Airlines canceled a handful of flights, according to Andrew Gestrine, airport operations coordinator at the Portland International Jetport. One American flight was canceled out of Bangor International Airport.

The slippery roads didn’t deter shoppers who crowded the Maine Mall in South Portland.

Amy Northrup, 47, and Sara Havard, 45, said they just took it slow driving up from Saco. In addition to getting a few gifts, the two friends planned to pick up Havard’s 18-year-old son, who was supposed to arrive at the jetport on a plane from Philadelphia. But his was one of the flights that was canceled, so they expected he would spend the night in Pennsylvania.

“It’s like ‘Home Alone’ in Philadelphia,” Havard said. “He’s excited, like, ‘I can get Chinese and stay at the hotel.’ ”

At 9:45 p.m. Saturday, Central Maine Power reported about 6,500 customers without power in its service area, including about 2,300 in both York and Cumberland counties.

The far northern part of Maine was under a winter storm warning late Saturday and into early Sunday, according to the National Weather Service station in Caribou. Five to 8 inches of snow and some icing are expected by early Sunday, making travel in northern Aroostook County “very hazardous or impossible,” the station said.

Closer to shore, a gale warning signaling winds of 34 to 47 knots was in effect until early Sunday in coastal Maine from Eastport to Stonington and 25 miles out to sea, according to the National Weather Service. A gale warning means only experienced sailors in properly outfitted vessels should be on the water, and all others are urged to seek safe harbor. The southern coastline from Stonington to Cape Elizabeth was under a gale warning until 7 p.m. Saturday.

The U.S. Coast Guard said it was not called out to any incidents on the water on Saturday.

Emily Higginbotham of the Morning Sentinel contributed to this report.