Two ships are due to arrive in the port of Thunder Bay on Monday, marking the latest start to a shipping season there.

An extremely cold winter left most of Lake Superior frozen over, and the ice in Thunder Bay harbour is still as much as a metre thick in some places.

A U.S. Coast Guard icebreaker has been working to break up the ice, but harbourmaster Guy Jarvis says a Canadian Coast Guard ship is on its way to help.

"We still ... have 36 to 42 inches of ice in the harbour. So a heavier icebreaker to continuously move the ice around will help," Jarvis said, adding he expects the CCGS Martha L. Black to arrive on Wednesday.

Jarvis says the effects of the cold have been felt throughout the province.

"Things in the lower Great Lakes were probably delayed 7-10 days because of the ice conditions in the Welland Canal and the St. Clair River, but I think winter's hanging around a little bit longer in the Lake Superior region," he said.

Jarvis says there are still as many as 50 ships waiting for an escort to cross Lake Superior.