“We turn out of our hammocks at 6.30am and lash up and stow in the usual way,” a Royal Navy sailor named Frank Baker wrote in his diary on December 6, 1917. “We fall in on the upper deck at 7am and disperse to cleaning stations, busying ourselves scrubbing decks etc. until 8am when we ‘cease fire’ for breakfast.” Baker was pulling wartime duty as a ship inspector in the harbor of Halifax, Nova Scotia, on the lookout for spies, contraband and saboteurs.

But there were no ships to be inspected that day, so after breakfast he and his crewmates aboard HMCS Acadia went back to their cleaning stations. “We...had just drawn soap and powder and the necessary utensils for cleaning paint work,” he wrote, “when the most awful explosion I ever heard or want to hear again occurred.”

What Frank Baker heard was the biggest explosion of the pre-atomic age, a catastrophe of almost biblical proportions. The 918 words he wrote for December 6 make up the only eyewitness account known to be written on the day of what is now called the Halifax Explosion. After World War I, his diary sat unread for decades. Now, it has been included in an exhibit on the explosion’s centennial at the Dartmouth Heritage Museum, across the harbor from Halifax. It is published here for the first time.

“The first thud shook the ship from stem to stern and the second one seemed to spin us all around, landing some [crew members] under the gun carriage and others flying in all directions all over the deck,” Baker wrote. Sailors 150 miles out to sea heard the blast. On land, people felt the jolt 300 miles away. The shock wave demolished almost everything within a half-mile. “Our first impression was that we were being attacked by submarines, and we all rushed for the upper deck, where we saw a veritable mountain of smoke of a yellowish hue and huge pieces of iron were flying all around us.”

Unseen by Baker, two ships had collided in the Narrows, a strait linking a wide basin with the harbor proper, which opens into the Atlantic to the southeast. An outbound Belgian relief ship, the Imo, had strayed off course. An inbound French freighter, the Mont-Blanc, couldn’t get out of its way. The Imo speared the Mont-Blanc at an angle near its bow. The freighter carried 2,925 tons of high explosives, including 246 tons of benzol, a highly flammable motor fuel, in drums lashed to its deck. Some of the drums toppled and ruptured. Spilled benzol caught fire. The Mont-Blanc’s crew, unable to contain the flames, abandoned ship.

The ghost vessel burned and drifted for about 15 minutes, coming to rest against a pier along the Halifax shore. Thousands of people on their way to work, already working at harborside jobs, or at home in Halifax and Dartmouth, stopped in their tracks to watch.

Then the Mont-Blanc blew.

“A shower of shrapnel passed over the Forecastle, shattering the glass in the engine room and chart room to smithereens, which came crashing down into the alleyways,” Baker wrote. “...The fires all burst out on to the floor of the stokehold [the engine room’s coal storage] and it was a marvel that the stokers were not burned to death, but all of them escaped injury as did all the other of the ship’s company.

“A tug was alongside us at the time and part of her side was torn completely out and three of the crew were injured, one of them getting a piece of flesh weighing nearly 2 pounds torn off his leg. A hail of shrapnel descended about 20 yards from the ship, this came with such force that had it struck us we should certainly have all been lost.”

The Mont-Blanc had disintegrated, showering iron fragments and black tar across Halifax; the shaft of its anchor, weighing 1,140 pounds, spiked into the earth more than two miles away. The explosion tore a hole in the harbor bottom, unleashing a tidal wave that tossed ships as if they were bathtub toys and washed away a Mi’kmaq fishing settlement that had been at the northwestern end of the basin for centuries. A volcanic plume of gray smoke, sparkling fragments and flame rose miles into the sky before billowing outward.

“This was the last of the explosion, the whole of which had taken place inside of five minutes,...” Baker wrote. “Then came a lull of a few minutes and when the smoke had cleared sufficiently, we saw clearly what had happened....One ship had been hurled wholesale for a distance of about 400 yards, dashing it close to the shore, a total wreck with dead bodies battered and smashed lying all around in disorder.

“Fires broke out on ships all around and hundreds of small crafts had been blown to hell and the sea presented an awful scene of debris and wreckage. Our doctor attended to the wounded men on the tug as quickly as possible and we laid them on stretchers in a motor boat and took them to hospital. The scene ashore was even worse.

“The N.W. part of Halifax was in total ruins and fires were springing up all over the city. Part of the railway was completely demolished and everywhere were dead and dying among the ruins. When we arrived at the hospital, the windows were all blown out and the wards were two feet deep in water owing to all the pipes having burst. We had to return to our ship as quickly as possible, as we are Guard Ship and responsible for the safety of the other vessels in harbour.”

Back on the Acadia, Baker beheld a desolate scene: “What a few hours before had been beautiful vessels, were now terrible wrecks, their crews all dead and bodies, arms, etc. were floating around in the water.” That afternoon the Acadia’s crew was called upon to quell a mutiny aboard the Eole, a French ship running relief for the Belgians. After doing so, they returned to their ship. “We quickly got hurried tea and proceeded ashore,” Baker wrote. “Here the scene was absolutely indescribable.

“The town was literally ablaze, the dry dock and dockyard buildings completely demolished and everywhere wounded and dead. The theatres and suitable buildings were all turned into hospitals or shelters for the accommodation of the homeless. Naval and Military pickets were patrolling the streets endeavouring to keep order. Poor little kiddies homeless, their parents having perished, were crying piteously and anxious relatives were inquiring for their dear ones.”

Virtually no family was untouched. By then, most of the nearly 2,000 known fatalities from the blast had occurred—though many bodies were unidentifiable. Some 9,000 were injured, many of them children—wounded in the face and eyes as they gazed out windows at the burning Mont-Blanc. Some 6,000 people were left homeless, and many thousands had to bed down in badly damaged houses. The coming morning would bring a blizzard and deep cold.

Ashore, “we visited the part where the fires were at their worst, and it is beyond me to describe the absolute terror of the situation,” Baker wrote. “For miles around nothing but a flaming inferno, charred bodies being dragged from the debris and those poor devils who were left still lingering were piled into motor wagons and conveyed to one of the improvised hospitals. We returned to our ship at 11pm sick at heart with the appalling misery with which the city abounded. The glare from the fires lighting the harbour up like day, on the other side of the bay, the little town of Dartmouth was also in flames on sea and land nothing but misery, death and destruction....I cannot help but marvel that we escaped.”

But Baker survived, and he served until March 1919. Then he settled in Kettering, about 80 miles north of London, with his diary, October 9, 1917, to January 14, 1918. In 1924, he married Jessie Liddington, from the nearby village of Pytchley; they had four sons. Eventually, he became head of a chain of butcher shops and meat-supply facilities. After retiring, in 1973, he moved to Australia, where two of his sons and many of his grandchildren were living. Two years later, he learned he had cancer.

At that point, he passed the diary and some photographs from his time aboard the Acadia to his son “without any explanation,” the son, Rex, told me. After his father died, in 1977, “I put them away and forgot about them for over 30 years.”

Only after Rex retired—he’s 72 now, and living in Busselton, a seaside town south of Perth—did he pull the diary from the bureau drawer where he’d stowed it. Once he read it, he suspected that it might have historical significance, so in January 2016 he contacted Bonnie Elliott, director of the Dartmouth Heritage Museum. When she read it, she says, “I fell off a log. I knew this diary was really important.”

Rex Baker carried the diary himself to Canada. While there, he boarded the Acadia, which is now a floating museum in Halifax Harbor, for the first time. Elliott met him as he stepped off the ship. “There were tears in his eyes,” she recalls.

Baker says his father “spoke to no one in the family about that experience at all.” After reading the diary, though, he says that as he walked about the Acadia, “I felt almost a presence. Like he was standing behind me.”