In a sure sign of spring, a United States Coast Guard vessel is expected to begin ice breaking in Thunder Bay's harbour this weekend, clearing a path for ships to move into and out of the local port.

The cutter Alder was initially expected to be clearing ice in Thunder Bay last Monday. However, heavy ice buildup in its home port of Duluth, Minnesota, kept it there longer than anticipated, a spokeswoman for Fisheries and Oceans Canada said in an email to CBC News.

"The USCGC Alder broke through the ... ice blocking their departure from Duluth-Superior this week," Lauren Solski said. "The ship has some additional work to complete this week."

The Alder is expected to arrive in Thunder Bay by Sunday, March 18, where it will begin ice breaking operations in the harbour. Despite the delay, the ship is still arriving ahead of the opening of the Soo Locks on March 25.

The Alder will also have support from the Canadian Coast Guard's Samuel Risley ship, the Solski said, which will be arriving in Thunder Bay next week for ice breaking and ship escorting.

Ice will be unstable

Fisheries and Oceans reminds people the ice may become unstable and dangerous during ice breaking activities.

Anyone who uses the ice recreationally — for fishing, riding all-terrain vehicles, walking, or snowmobiling, for example — is asked to clear the ice while ice breaking is taking place.

People are also reminded to use extra caution after ice breaking ships have left, as the ice may remain unstable for some time.