Sudbury, Ontario tornado

The Sudbury tornado was an F3 tornado, which hit the Canadian city of Sudbury, Ontario, at approximately 8:30 a.m. on August 20, 1970.

It is currently tied for the status of the eighth deadliest tornado in Canadian history.

Considered unusual because tornadoes of this strength rarely occur in Northern Ontario, the tornado touched down in the suburban community of Lively. The tornado tracked quickly eastward into the city, hitting the neighbourhoods of Copper Cliff, Robinson and Lockerby over the next ten minutes. Another tornado associated with the same storm also hit the community of Field, approximately 50 kilometres east of Sudbury, less than an hour later.

The storm continued through North Bay, uprooting some trees in the wilderness but avoiding any damage to the city. It then tracked southeasterly toward Ottawa, leading the federal government to order a precautionary shutdown of its offices in the capital, but the storm weakened around Chalk River and only a few millimetres of rain actually fell on Ottawa by the time it reached that city.

Residents of the region had little warning of the storm as the Sudbury Airport did not at the time have weather radar capable of detecting tornado activity, and the day's only weather forecast was for "showers". The first public indication of the twister, instead, was a phone call to CKSO from a woman frantically reporting that her house was blowing away.

Six people died and 200 were injured in the tornado, which caused an estimated $17 million ($106 million in 2017 dollars) in damage, including to Inco's copper smelter in Copper Cliff. A pipeline carrying iron-nickel concentrate to the plant collapsed onto a train track below, in turn causing a derailment when a train hit the collapsed pipe, but the incident resulted in only minor injuries. The Inco Superstack, then under construction, swayed in the storm but was not heavily damaged. Six workers were on the construction platform at the time; although all six survived, they quit their jobs the next day.

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Wikipedia