Emergency crews have called off the search for a missing South Shore woman, who fell out of a kayak after striking a navigational buoy near the Old Port of Montreal.

The woman and her husband, both in their 40s, were kayaking around 12:30 p.m. in the St. Lawrence River, heading toward Montreal from the Boucherville Islands.

"Their kayak was caught up in the heavy current and slammed against the navigation buoy. Part of the kayak was actually dragged under the buoy, underwater," said CTV Montreal reporter Derek Conlon, reporting live from the Clock Tower Pier in the Old Port of Montreal.

The man managed to get out of the boat, but the woman did not.

A tour boat that had left the Old Port spotted the man yelling for help and was able to rescue him – but there was no sign of his wife.

An afternoon-long search and rescue operation, which included boats and helicopters, proved to be futile.

"The water is very cold, and unfortunately the chances of survival are very slim," said Conlon.