Every winter in Montreal, visitors are treated to a portside symphony played by boat foghorns and train whistles.

The Port Symphonies, performed since 1995, make use of the shipping boats moored in the frozen St Lawrence River. Normally used to transport merchandise between cities along the Great Lakes and Montréal, the ships remain bound in ice from January to mid-March.

Just like other instruments, each boat horn has a unique sound, and the composer (who changes from year to year) arranges a different score every January. Past compositions have included train whistles and the bells of nearby Notre Dame Basillica, and about 30 volunteers are needed to “play” the horns and other instruments.

On the afternoon of 4 March, the frozen Port of Montreal will again come alive with sound. This year’s symphony was composed by Mumbai-born Sandeep Bhagwati, who substituted fog horns in place of the traditional Indian tambura, an instrument normally used to create an ongoing drone sound before and after the other instruments stop playing. Singers will move throughout the crowd for a sound that is meant to imitate the ebb and flow of the St Lawrence River.

Though most gather for the free concert in front of the Pointe-à-Callière Montréal Museum of Archaeology and History, which sponsors the annual outdoor event, the sounds can be heard throughout Old Montreal.