1917 December 6th. The Halifax Explosion.

Halifax Explosion

Halifax Explosion
A view of the pyrocumulus cloud, most likely taken from the present-day location of the dock at the Bedford Institute of Oceanography (BIO) looking from Bedford Basin southeast toward The Narrows, approximately 15-20 seconds after the explosion.
Location	Halifax, Nova Scotia, Canada
Date	December 6, 1917 9:04:35 (AST)
Deaths	2,000 (approximate) (1,950 known)
Non-fatal injuries	9,000 (approximate)

The Halifax Explosion occurred in Halifax, Nova Scotia, Canada, on the morning of December 6, 1917. SS Mont-Blanc, a Frenchcargo ship fully loaded with wartime explosives, was involved in a collision with the Norwegian vessel SS Imo in the Narrows, a strait connecting the upper Halifax Harbour to Bedford Basin. Approximately twenty minutes later, a fire on board the French ship ignited her explosive cargo, causing a cataclysmic explosion that devastated the Richmond District of Halifax. Approximately 2,000 people were killed by debris, fires, and collapsed buildings, and it is estimated that nearly 9,000 others were injured. The blast was the largest man-made explosion prior to the development of nuclear weapons, with an equivalent force of roughly 2.9 kilotons of TNT. In a meeting of the Royal Society of Canada in May 1918,Dalhousie University's Professor Howard L. Bronson estimated the blast at some 2400 metric tons of high explosive. 

Mont-Blanc was under orders from the French government to carry her highly explosive cargo overseas to Bordeaux, France. At roughly 8:45 am, she collided at slow speed (1 to 1.5 miles per hour or 1.6 to 2.4 kilometres per hour) with the 'in-ballast' (without cargo) Imo, chartered by the Commission for Relief in Belgium to pick up a cargo of relief supplies inNew York. The resultant fire aboard the French ship quickly grew out of control. Without adequate and accessible firefighting equipment, the captain, pilot, officers and men were forced to abandon her within a few minutes following the accident. Approximately 20 minutes later (at 9:04:35 am), 

Mont-Blanc exploded with tremendous force. Nearly all structures within a half-mile (800 m) radius, including the entire community of Richmond, were completely obliterated. A pressure wave of air snapped trees, bent iron rails, demolished buildings, grounded vessels, and carried fragments of the Mont-Blanc for kilometres. Hardly a window in the city proper survived the concussion. Across the harbour, in Dartmouth, there was also widespread damage. A tsunami created by the blast wiped out the physical community of Mi'kmaq First Nations people that had lived in the Tuft's Cove area for generations. There were a number of casualties including five children who drowned when the tsunami came ashore at Nevin's Cove.