At 9:04:35 am, the out-of-control fire aboard
Mont-Blanc finally set off her highly explosive cargo.
[53] The ship was completely blown apart and a powerful
blast wave radiated away from the explosion at more than 1,000 metres (3,300 ft) per second. Temperatures of 5,000 °C (9,030 °F) and pressures of thousands of atmospheres accompanied the moment of detonation at the centre of the explosion.
[54][23] White-hot shards of iron fell down upon Halifax and Dartmouth.
[55] Mont-Blanc's forward 90 mm gun, its barrel melted away, landed approximately 5.6 kilometres (3.5 mi) north of the explosion site near
Albro Lake in Dartmouth, while the shank of her anchor, weighing half a ton, landed 3.2 kilometres (2.0 mi) south at
Armdale.
[56]
An area of over 160 hectares (400 acres) was completely destroyed by the explosion,[56] while the harbour floor was momentarily exposed by the volume of water that vaporized. A
tsunami was formed by water surging in to fill the void;
[59] it rose as high as 18 metres (60 ft) above the high-water mark on the Halifax side of the harbour.
[60]
Over 1,600 people were killed instantly and 9,000 were injured, more than 300 of whom later died.
[23] Every building within a 2.6-kilometre (1.6 mi) radius, over 12,000 in total, was destroyed or badly damaged.
[59] Hundreds of people who had been watching the fire from their homes were blinded when the blast wave shattered the windows in front of them.
[64] Stoves and lamps overturned by the force of the blast sparked fires throughout Halifax,
[65] particularly in the
North End, where entire city blocks were caught up in the inferno, trapping residents inside their houses. Firefighter Billy Wells, who was thrown away from the explosion and had his clothes torn from his body, described the devastation survivors faced: "The sight was awful, with people hanging out of windows dead. Some with their heads missing, and some thrown onto the overhead telegraph wires." He was the only member of the eight-man crew of the fire engine "Patricia" to survive.
[66]
Large brick and stone factories near Pier 6, such as the Acadia Sugar Refinery, disappeared into unrecognizable heaps of rubble, killing most of their workers.
[67] The Nova Scotia cotton mill located 1.5 km (0.93 mile) from the blast was destroyed by fire and the collapse of its concrete floors.[68] The Royal Naval College of Canada building was badly damaged, and several cadets and instructors maimed.
[69]
The city's industrial sector was in large part gone, with many workers among the casualties and the dockyard heavily damaged.
[105]