The frigid temperatures and end-of-season shipping rush on the Great Lakes have led to a traffic jam of giant 1,000-foot ships on Lake Superior outside Duluth.
On New Year's Day there were nine huge freighters anchored outside the Aerial Lift Bridge in Duluth — arranged like in a game of Battleship — steam from the lake billowing around them, all waiting to load up with iron ore pellets in Duluth, Two Harbors, or Superior, Wis.
And another dozen or more ships are scheduled to arrive in the next week to load up with taconite pellets.
So why are they all anchored outside Duluth?
"One, it's a great place to sit and wait — free parking as we say," said Adele Yorde, spokesperson for the Duluth Seaway Port Authority.
• Photos, video: Frigid temps bring gorgeous sea smoke to Duluth
It's shallower off Duluth than Two Harbors, she said, so ships will wait outside Duluth until one of the ore docks opens there.
It's also the end-of-season shipping rush, when steel mills in the lower Great Lakes are eager to bolster their stockpiles of taconite pellets so they have enough steel-making material to last through the 10-week closure of the Great Lakes shipping season, which begins around mid-January, after the Soo Locks close between Lake Superior and Lakes Michigan and Huron.
Ships sometimes also have to wait for trains to deliver loads of pellets from taconite mines on the Iron Range.
Additionally, the frigid temperatures are slowing down loading at the ore docks. In July, it takes about 8 to 10 hours to load a 1,000-foot vessel with taconite pellets. That can double in cold conditions, when taconite pellets can freeze together in rail cars and conveyor belts can break.
Ice cover on the lakes is so far not hampering shipping traffic, said Yorde. There is a fleet of nine ice breakers on the lakes, keeping shipping channels clear. The lakes are about 20 percent ice covered.
During the winter of 2013-2014, ships waited to be escorted by icebreakers in giant convoys across the lakes. That hasn't happened yet. But it doesn't mean it isn't chilly for the crews on the boats.
"I keep reminding people, if you think we're cold on land, try being on a steel boat," Yorde said. "The freezing temperatures are just incredible."