The Halifax explosion

For many, it was the worst battlefield carnage they would see in the whole war, and it was here on the home front.
A view of Halifax two days after the explosion. Imo is visible aground on the far side of the harbor.

Shipbuilding in Nova Scotia dates to 1606. By the eighteenth century, the Canadian Maritimes were a global boatbuilding center. Their importance increased when Britain banned the United States from the West Indies trade after the American Revolution.

By December, 1917, Halifax was a bustling Canadian port of 60,000 people, with a recently renovated harbor. On December 6, it was destroyed in a spectacular military disaster. About 2,000 people were killed and 9,000 others were injured, including a Mi’kmaq village that was destroyed by the resulting tsunami. Until Hiroshima, this was the largest explosion humankind ever created.
St. Joseph’s Convent, located on the southeast corner of Göttingen and Kaye streets. The last body from the Halifax explosion wasn’t recovered until 1919.
Halifax and Dartmouth lie on opposite sides of a deep natural harbor. To get into its protected basin, boats traverse a narrow glacial channel that separates the two cities. Halifax Harbour is on the fastest sea route between Europe and North America. The success of German U-boat attacks had led the Allies to institute the convoy system. Halifax was a major western staging point. As the war raged, the port bustled with troop ships, relief supplies, and munitions ships forming up to cross the Atlantic.
The harbor was protected by two sets of submarine nets. These were raised and lowered each night.
On the night of December 5, the French freighter Mont Blanc arrived too late to clear the submarine nets. She would enter the harbor the following morning under the command of an experienced harbor pilot, Francis Mackey. The freighter was carrying a highly-volatile cargo of 2,300 tons of picric acid, 200 tons of TNT, 35 tons of benzole, and 10 tons of gun cotton. Mackey asked for special protections during her transit of the narrows. He didn’t get them.
Halifax boatyard after the explosion.
As soon as the nets were lowered, Mont Blanc started up channel. Meanwhile, the Norwegian vessel Imo left its mooring, bound for New York. She was hustling, trying to make up for lost time, and was on the wrong side of the channel. The two ships had what we might describe as a fender-bender. Unfortunately, the barrels of benzole toppled and flooded Mont Blanc’s hold. Sparks from Imo’s engines lit the mess into an uncontrolled conflagration.
SS Imo aground after the explosion.
Mont Blanc’s crew quickly abandoned ship. People gathered on the waterfront to watch the burning boat drifting onto the docks. As the fire department arrived, Mont Blancexploded in a blinding flash of raw energy.
In addition to the terrible loss of life, Halifax’s waterfront was leveled. Over 12,000 homes were damaged or destroyed. Hundreds of people were blinded by flying glass. Overturned stoves and lamps sparked fires across the city. People were killed by the explosion, the resulting fires, or by flying debris.
Kathleen Malloy, victim of the Halifax Explosion, sits up in a hospital bed, likely at Pine Hill Convales­cent Hospital where injured babies were treated. (City of Toronto Archives)
Help came from many sources. Thousands of Canadian, British and American sailors and soldiers immediately sprang into action to create an emergency relief team. For many of them, this would be the worst battlefield carnage they would see. Doctors and nurses arrived by train. Among these was a large contingent from Boston, MA.
In 1918, Halifax sent a Christmas tree to the City of Boston in thanks. That tradition was revived in 1971. The tree is lit on Boston Commons each year and is the official Christmas tree of the city.