Halifax Explosion

Halifax Explosion
Tall cloud of smoke rising over the water
A view of the pyrocumulus cloud
LocationHalifax, Nova Scotia, Canada
Date6 December 1917
9:04:35 am (AST)
Deaths2,000 (estimate) (1,950 confirmed)
Non-fatal injuries
9,000 (approximate)
Part of a series on the
History of
Halifax, Nova Scotia
Halifax Town Clock.jpg

The Halifax Explosion was a maritime disaster in Halifax, Nova Scotia, Canada, which happened on the morning of 6 December 1917. The Norwegian vessel SS Imo collided with SS Mont-Blanc, a French cargo ship laden with high explosives, in the Narrows, a strait connecting the upper Halifax Harbour to Bedford Basin, causing a large explosion on the French freighter that devastated the Richmond district of Halifax. Approximately 2,000 people were killed by the blast, debris, fires or collapsed buildings, and an estimated 9,000 others were injured.[1] The blast was the largest man-made explosion at the time,[2] releasing the equivalent energy of roughly 2.9 kilotons of TNT (12,000 GJ).[3]

Mont-Blanc was under orders from the French government to carry her cargo of high explosives from New York City via Halifax to Bordeaux, France. At roughly 8:45 am, she collided at low speed, approximately one knot (1.2 mph or 1.9 km/h), with the unladen Imo, chartered by the Commission for Relief in Belgium to pick up a cargo of relief supplies in New York. On the Mont-Blanc, the impact damaged benzol barrels stored on deck that leaked vapors which were ignited by sparks from the collision, setting off a fire on board that quickly grew out of control. Approximately 20 minutes later at 9:04:35 am, the Mont-Blanc exploded.

Nearly all structures within an 800-metre (half-mile) radius, including the community of Richmond, were obliterated.[4] A pressure wave snapped trees, bent iron rails, demolished buildings, grounded vessels (including Imo, which was washed ashore by the ensuing tsunami), and scattered fragments of Mont-Blanc for kilometres. Across the harbour, in Dartmouth, there was also widespread damage.[1] A tsunami created by the blast wiped out the community of the Mi'kmaq First Nation who had lived in the Tufts Cove area for generations.

Relief efforts began almost immediately, and hospitals quickly became full. Rescue trains began arriving the day of the explosion from across Nova Scotia and New Brunswick while other trains from central Canada and the northeastern United States were impeded by blizzards. Construction of temporary shelters to house the many people left homeless began soon after the disaster. The initial judicial inquiry found Mont-Blanc to have been responsible for the disaster, but a later appeal determined that both vessels were to blame. There are several memorials to the victims of the explosion in the North End.


Cityscape bisected by central traintracks, with dense buildings to the left and harbourfront to the right
Looking north from a grain elevator towards Acadia Sugar Refinery, circa 1900, showing the area later devastated by the 1917 explosion

Dartmouth lies on the east shore of Halifax Harbour, and Halifax is on the west shore. Halifax and Dartmouth had thrived during times of war; the harbour was one of the British Royal Navy's most important bases in North America, a centre for wartime trade, and a home to privateers who harried the British Empire's enemies during the American Revolution, the Napoleonic Wars, and the War of 1812.[5][6]

The completion of the Intercolonial Railway and its Deep Water Terminal in 1880 allowed for increased steamship trade and led to accelerated development of the port area,[7] but Halifax faced an economic downturn in the 1890s as local factories lost ground to competitors in central Canada.[8] The British garrison left the city in late 1905 and early 1906.[9][10] The Canadian government took over the Halifax Dockyard (now CFB Halifax) from the Royal Navy.[11] This dockyard later became the command centre of the Royal Canadian Navy upon its founding in 1910.[12]

Just before the First World War, the Canadian government began a determined, costly effort to develop the harbour and waterfront facilities.[13] The outbreak of the war brought Halifax back to prominence. As the Royal Canadian Navy had virtually no seaworthy ships of its own, the Royal Navy assumed responsibility for maintaining Atlantic trade routes by re-adopting Halifax as its North American base of operations.[14] In 1915, management of the harbour fell under the control of the Royal Canadian Navy under the supervision of Captain Superintendent Edward Harrington Martin; by 1917 there was a growing naval fleet in Halifax, including patrol ships, tugboats, and minesweepers.[15]

The population of Halifax/Dartmouth had increased to between 60,000 and 65,000 people by 1917.[16] Convoys carried men, animals, and supplies to the European theatre of war. The two main points of departure were in Nova Scotia at Sydney, on Cape Breton Island, and Halifax.[17] Hospital ships brought the wounded to the city, and a new military hospital was constructed in the city.[18]

The success of German U-boat attacks on ships crossing the Atlantic Ocean led the Allies to institute a convoy system to reduce losses while transporting goods and soldiers to Europe.[19] Merchant ships gathered at Bedford Basin on the northwestern end of the harbour, which was protected by two sets of anti-submarine nets and guarded by patrol ships of the Royal Canadian Navy.[20]

The convoys departed under the protection of British cruisers and destroyers.[21] A large army garrison protected the city with forts, gun batteries, and anti-submarine nets. These factors drove a major military, industrial, and residential expansion of the city,[10] and the weight of goods passing through the harbour increased nearly ninefold.[22] All neutral ships bound for ports in North America were required to report to Halifax for inspection.[23]

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