DULUTH, Minn. - On America's largest body of fresh water, winter does not surrender easily.
Sometimes it needs convincing.
That's where the U.S. Coast Guard's cutter Alder comes in.
On March 6, the Alder and her crew broke their first ice in the Duluth-Superior harbor.
Cutting through ice 30 inches thick in places, the Alder's crew took 21 hours to go three miles.
"I had never seen anything like this before," said Boatswain Mate Second Class Jacob Nielsen, who arrived on the ship last summer from Maine.
Even Lake Superior veterans understand this polar vortex inspired winter is unique.
"They're saying this is the worst ice season since the mid-90s," says Tony Maffia, the Alder's captain. He calls it "a once in a generation-type of thing."
On the Alder's first day out ice covered 92 percent of the Great Lakes surface, the second-most ever measured.
On Monday, the Alder made its first trip under Duluth's aerial lift bridge, slowly cutting a path several hundred feet off the north shore of Lake Superior.
Chains rattle as the ship's two diesel engines, cranking 6,200 horsepower, propel the Alder's bow up onto the ice, which collapses under the stress.
"This ship just constantly moves, rocks, bounces," says Nielsen.
This season will be the greatest test for the Alder in her 10 years on the lake.
Normally weighing in a 2,000 tons, the ship has been loaded with three concrete buoy weights for good measure – each weighing 16,000 pounds.
Pressure ridges are the most challenging. Plates of ice buckling and stacking can create a ridge 5 feet thick. Though the propellers keep pushing, the Alder comes to a stop.
The ship reverses course 100 yards or so, then black diesel smoke pumps from its stack as it gathers speed and rams through a pressure ridge.
The process is repeated over and over during the course of a day, sometimes multiple times on the same ridge.
"You need a lot of patience," explains Maffia. "You can't drive it like you stole it."
Steel mills out east are hungry for Minnesota's iron ore, now piling up and waiting for shipment. Grain and cement must also be delivered.
Before the end of March, the Alder and her crew will have cut a path through more than 300 miles of ice, all the way to the locks at Sault Ste. Marie, Michigan. The Soo Locks are scheduled to open for the shipping season on March 25.
But even an ice breaker newcomer knows humility too goes a long way too.
"Absolutely," says Nielsen, casting an eye toward the lake. "You don't want to tease her too much, she might fight back."
Winter may be broken, but it still isn't beaten.
"We'll just call it a draw," smiles Nielsen.
Coast Guard cutter Alder plows through Lake Superior ice