The Madeline Island Ferry line will shut down service between Bayfield and La Pointe at the end of the day Friday, a few weeks later than normal.

"There's about six inches of solid ice and it's getting more difficult to get through,'' said Gary Russell, vice president of the ferry line. "And it's just brutal for our people to have to be out there, on the docks or the boats, in this cold."

At 9 a.m. Friday it was 13 below zero in Bayfield with a 31 below zero wind chill. The forecast calls for continued brutally cold temperatures through next week.

Russell said the shutdown may leave island residents briefly without a water option to get to the mainland as service by air-powered "windsleds'' might not start until Monday. Neither a recorded message at Windsleds Inc. on Friday nor the company's website were clear on when the sleds may be up and running.

Until ferry service resumes, usually about April 1 after a normal winter, island residents and visitors will count on the windsleds and then, once ice thickens enough, a plowed ice road that enables driving back and forth to the mainland. Island regulars like the ice road best because it's free, and they can come and go on their own schedule.

The long-term average for a last day of ferry service is near Jan. 1 but has been moving later in recent decades as average air and water temperatures have risen.

"We haven't had a December closing since I don't know when,'' Russell said. "For the last 25 years it's been later and later."

In the winters of 2012 and again in 2016 and 2017 the ferry ran all year, without stopping. That's hard on the boats and the crews, Russell noted. More than 150 years of ferry records the ferry ran all winter only in 1998, 2012, 2016 and 2017. A review of records over the year showed the ferry operating season has been growing steadily, with shorter ice-bound closures.

From March 28, 2015 to Jan. 5, 2018 the ferries logged 1,019 days of service, by far a record for the ferry line.

About 300 people live on the island year-round.