​On November 13, 1961, Toronto, Ottawa, Windsor, North Bay, and cities across Canada were destroyed by nuclear bombs. More than 2 million people were incinerated and another 1.5 million were burned or exposed to fatal levels of radiation in the deadliest single military attack in the history of the world.

Or at least that’s what happened on paper.

The spectacular scale of death and destruction was part of a simulation conducted at the height of the Cold War as an element of the largest emergency preparedness drill ever undertaken in Canada.

The test, named Tocsin II, or Tocsin B, was the third exercise of its kind attempted in Canada and the second in 1961. Conceived under Prime Minister John G. Diefenbaker, the Tocsin tests were essentially public dress rehearsals for the day the bomb might eventually fall.

Throughout the 1950s and into the ’60s, tensions between America and the USSR were at an all-time high, and fear of a new kind of weapon was growing in both countries.

In November 1952, the U.S. had tested the first full-scale thermonuclear device in the Enewetak Atoll in the Pacific Ocean. The bomb, codenamed Ivy Mike, exploded with the equivalent force of 10.5 megatons of TNT and created a fireball five kilometres wide. (For comparison, the bombs dropped in Hiroshima and Nagasaki during the Second World War had the equivalent force of about 0.02 megatons of TNT.)

Ivy Mike had the power to raze about 50 square kilometres — enough to wipe out the core of a major city like Moscow or St. Petersburg.

The Soviets had their own hydrogen bomb program and began to develop devices just as deadly, testing them in present-day Kazakhstan and on remote islands in the Arctic Ocean. 

A map published in a 1961 edition of the Toronto Daily Star shows the potential effects of a nuclear attack on the city. (Toronto Star)

Suddenly, an unimaginably destructive arsenal was available to two feuding world superpowers, and Canada was directly between them.

Though Canada was unlikely to be a target, a nuclear strike on Detroit could have wiped out Windsor; an attack on Buffalo could have rained toxic fallout on Niagara Falls, Hamilton, and the GTA.

If bombs had fallen on Canadian cities, the destruction would have been unimaginable. A coordinated assault on major population centres would have killed millions and rendered the land a toxic wasteland for years.

In the 1950s, the Canadian government believed mass evacuation was the best course of action in the event of nuclear attack. Given warning of an approaching bomber, thousands would be able to safely exit cities via highways, provided they had access to cars and were physically mobile.

But the invention of intercontinental missiles changed this calculus. The warning time for a nuclear attack could be as little as 15 or 20 minutes if a long-range rocket were involved. In light of this development, civil-defence procedures became focused on home shelters capable of keeping out radioactive ash ejected from the explosion.

In 1960, the federal government under Diefenbaker printed a booklet titled Your Basement Fallout Shelter: Blueprint for Survival No. 1, which detailed how to build a shelter from scratch.

Citizens were encouraged to set aside a portion of their basement for construction of a shelter capable of sustaining life for several days. Stocked with canned food and water, a transistor radio, and enough bags to store excrement, such a structure could keep a family safe from harm until the worst of the danger had passed.

 Some home builders even offered basement shelters as optional extras to tempt buyers. The Regency Acres subdivision in Aurora, Ontario, for example, offered a reinforced concrete shelter with air filters and metal doors for an additional $1,500.

Of course, basement shelters protected only families wealthy enough to own their own homes. The City of Toronto looked into altering the City Hall parking garage or the Bloor-Danforth subway line in order to use them as public shelters but ultimately didn’t pursue the idea.

Opponents of the basement shelter program urged the government to focus on disarmament. “Civil defence is important,” said Lester B. Pearson, who was then the leader of the opposition. “But policies in all countries to make civil defence unnecessary are even more important.”

The first Tocsin civil-defence exercise involving the federal and provincial governments took place in 1960, after the U.S.S.R., under Nikita Khrushchev, and the U.S. had agreed to suspend nuclear testing.

During the exercise, key members of the government and high-ranking civil servants were evacuated to military bases away from population centres.

The Ontario government was directed to CFB Borden (then Camp Borden), near Barrie, marking the first time the provincial cabinet had met outside Toronto. The federal government went to Garrison Petawawa on the Ottawa River northwest of the capital.

An escalation in tensions between the U.S. and U.S.S.R. and an end to the nuclear testing moratorium in 1961 prompted the federal government to broaden the scope of its civil-defence exercises.

In March of that year, Ottawa announced Tocsin 1961, a major civil-defence exercise that would involve the federal government, all provincial and territorial governments, and 500 municipalities nationwide.

An alert would be sounded at some time on May 5. Governments would then activate their emergency continuity plans, sounding air-raid sirens and evacuating key personnel to remote control centres.

Metropolitan Toronto’s nuclear attack HQ was in the basement of a historic farmhouse and former home for the aged in Aurora, Ontario. It featured a hand-drawn map of the Metro area, and boards for keeping track of the dead or injured. Phone lines connected the shelter with the Ontario HQ at CFB Borden and the federal control centre at Petawawa.

Tocsin 1961 began at 11 a.m. with a nationwide broadcast by Diefenbaker. Within 15 minutes of the address, Governor General Georges Vanier had signed and officially sealed a dummy version of the War Measures Act.

The first paper bomb fell on Cold Lake, Alberta, at 11:20, and then all hell broke loose. “A total of 17 nuclear devices — two delivered by inter-continental ballistics missiles, the others by aircraft — were reported to have hit the country,” reported the Globe and Mail the day after the exercise.

“Preliminary army assessments placed the numbers of Canadians killed or likely to die at 1,750,000. Another 1,500,000 were injured, sick from the effects of radiation or likely to become sick. There were 1,000,000 in need of rescue.”

Despite the simulated chaos, the exercise appeared to go smoothly enough. Many sirens across the country sounded within 39 seconds of the alert, and 200 key federal figures managed to assemble safely at Petawawa and perform the basic functions of government. 

Fallout-shelter ad that appeared in the Toronto Daily Star on January 17, 1959. (Source: Toronto Star)

It wasn’t perfect, though, and Diefenbaker told Parliament there were “gaps” that needed to be addressed before the next exercise. In some cities, the alert sirens failed to sound at the crucial moment. Diefenbaker also felt communication between the various governments could have been better.

Cold War tensions continued to rise in the months that followed Tocsin 1961. The Berlin Crisis, which led to the construction of the Berlin Wall, played out that summer, and in October, the Soviets exploded the RDS-220 hydrogen bomb.

Nicknamed “Tsar Bomba,” it was the most powerful nuclear weapon ever detonated — five times more powerful than Ivy Mike and 2,500 times more powerful than the nuclear bombs dropped in Japan in the Second World War.

Increasingly concerned, the Diefenbaker government hurriedly arranged a third Tocsin test for November.

Tocsin B would be the biggest civil-defence exercise ever attempted in Canada. Sirens would again sound across the country, and every TV and radio station would broadcast a special program designed to make it seem as though a real attack had taken place.

“This is a national emergency. An enemy attack on Canada is considered probable,” said a man’s voice on the radio on November 13.

“On the authority of the Canadian government, sirens in Canada are sounding or have sounded the alert warning. This means the government expects an enemy attack on North America. Listen for further instructions.”

A message from Diefenbaker, reassuring listeners that the broadcast was only a test, followed the sound of air-raid sirens.

As radios, TVs, and sirens across Canada blared, select members of municipal, provincial, and federal governments retreated to their various command posts by bus and helicopter.

The “Diefenbunker” underground shelter in Carp, Ontario, wasn’t finished yet, so cabinet ministers took refuge in underground facilities at Garrison Petawawa.

Bombs fell on 14 Canadian cities: Courtenay, British Columbia; Cold Lake, Alberta; Churchill, Manitoba; Iqaluit, then-Northwest Territories; Chatham, New Brunswick; and Goose Bay and Stephenville, Newfoundland and Labrador. Vancouver, Edmonton, Montreal, and Halifax were hit, and in Ontario, so were North Bay, Ottawa, and Toronto.

Windsor was destroyed when a 10-megaton bomb was dropped on Detroit, and a five-megaton explosion at Yonge and Bloor streets killed 630,000 people in Toronto — “everyone south of Lawrence, west of Victoria Park, east of Dufferin,” as the Toronto Daily Star noted.

The other Ontario bombs were also five megatons: 36,000 died in North Bay, and 142,000 died in Ottawa.

“Most of heavily-populated Ontario, according to the theorists, was blanketed with fallout from bombs in upper New York state and Michigan. West winds carried the fallout across the province,” reported the Toronto Daily Star.

Worst-case scenario for fallout from a nuclear strike on Detroit or Buffalo, from a 1961 report titled “Feasibility report on the use of the Toronto subway system and civic centre garage as fallout shelters,” by the Foundation of Canada Engineering Corporation.

All the warheads were delivered by aircraft or surface-to-air missile. Three submarines had been lurking off Canada’s coasts but did not fire.

“Everything went according to plan,” reported the Globe and Mail.

In all, 1.5 million were injured and 2.2 million people were killed, including Diefenbaker, who died in the basement of 24 Sussex Drive when the bomb hit Ottawa. Governor General Vanier died in the same blast.

A third to a half of the country’s industry was destroyed, half of the hydro generating stations were wrecked, and a quarter of Canada’s petroleum refineries lay in ruins.

Questions remained after the test: Could military forces shoot rioters and looters? What would happen when the country’s banks shut down? Who would evacuate the sick? Could survivors be conscripted into the army or police?

“It is self-apparent that if out of a population of 18 million we lose almost one-third in a nuclear attack it is appalling,” said Defence Minister Douglas Harkness, who acted as PM during the test. “But there would be sufficient people left to reconstitute the life of the country.”

Not everyone agreed.

“Survival is not possible — or even desirable — in the event of another war,” wrote J. Gordon in a letter to the editor of the Toronto Daily Star.

“Imagine yourself wading knee-deep in thousands of dead, dying, mutilated bodies — some of whom will be your children, parents, friends. For this is certainly what will happen.”

The country organized and participated in civil-defence exercises in the ’60s and ’70s, but nothing on the scale of Tocsin B was ever again attempted in Canada. The government did, though, continue to urge Canadians to be vigilant in the face of a potential nuclear threat.

“We cannot and must not close our eyes to the dangers that may beset us,” said Diefenbaker.

“Failure on the part of the government and of the people to plan and prepare for the awesome eventualities should nuclear war be launched would be inexcusable — and worse.”

Chris Bateman is a freelance journalist whose work has appeared in the National Post, Spacing, and Toronto Life.