The Halifax explosion
The naval accident that erased an entire city in Canada
Alex Q. Arbuckle
Dec. 6, 1917
Halifax Harbor in Nova Scotia supports the communities of Halifax on the west shore and Dartmouth on the east shore. By 1917, the harbor area was home to 65,000 people, and it was a critical naval hub in World War I.On Dec. 6, 1917, the Norwegian ship SS Imo was sailing out with relief supplies bound for Belgium, and was speeding to make up for delays. Meanwhile, the French ship SS Mont-Blanc was sailing into the harbor, seeking to rendezvous with a convoy staging in Bedford Basin, the wide inner harbor on the far side of the narrow strait separating Halifax and Dartmouth. The Mont-Blanc was laden with a full cargo of guncotton, TNT, picric acid and benzole fuel.
Just like driving on a road, ships were expected to keep to their right — or starboard — when traveling through the Narrows. As the Imo entered the strait, it encountered a ship approaching on the wrong side, forcing the captain to swerve across to the opposite side. But there was a tugboat in the middle of the channel, blocking him from crossing into the other lane. Entering the Narrows from the ocean, the captain of the Mont-Blanc saw that the Imo was on a collision course when they were less than a mile apart. Both captains tried to signal to each other with whistle blasts to change course, and cut their engines as their momentum carried them ever closer. Fearful of running aground and setting off his explosive cargo, the captain of the Mont-Blanc swung his bow toward the middle of the channel, just missing the other ship. The captain of the Imo, meanwhile, reversed his engines, which sent his bow swinging into the Mont-Blanc’s starboard side.It was a glancing blow, but enough to topple and crush barrels of flammable benzole, which were quickly ignited by the sparks of the two ships’ hulls grinding against each other. A fire was soon raging out of control on the Mont-Blanc.Knowing the cargo could go off at any second, the crew of the Mont-Blanc abandoned ship, fleeing for the Dartmouth shore as the ship drifted up and ran aground on the Halifax shore near Pier 6. Citizens of Halifax and Dartmouth, unable to hear the desperate warnings of the fleeing sailors, flocked to their windows to watch the spectacle of the burning ship. Nineteen minutes after the collision, the Mont-Blanc detonated in a 2.9-kiloton explosion.
The force was equivalent to one-fifth of the atomic bomb dropped on Hiroshima. The Mont-Blanc ceased to exist, as 9,000-degree temperatures vaporized it and enough water to briefly expose the bottom of the harbor. The pressure wave flattened nearly every building within a mile and a half, killing more than 1,600 people. Thousands more were critically injured.As a smoke cloud climbed nearly 12,000 feet into the atmosphere, the sky rained hot metal shrapnel. A tsunami rose 60 feet over the shore and tossed the Imo onto the Dartmouth side. People who had been watching the fire were blinded or killed by flying glass. Hundreds of fires were sparked all over Halifax and Dartmouth. An incoming passenger train was stopped outside the blast radius thanks to the sacrifice of a railway dispatcher who stayed at his post to send out a warning.Within three hours of the blast, officials had formed an official Halifax Relief Commission as soldiers, sailors and citizens worked to rescue victims from crumbling buildings and extinguish the fires consuming swaths of land.The day after the explosion, a blizzard dumped 16 inches of snow on the city, stalling relief efforts but extinguishing the remaining fires. In total, nearly 2,000 people were killed, and 9,000 injured in the largest manmade explosion before the development of nuclear weapons.
Hold up the train. Ammunition ship afire in harbor making for Pier 6 and will explode. Guess this will be my last message. Goodbye boys. - Final communication from railway dispatcher Patrick Vincent Coleman
