Toronto has the most tower cranes in North America — but are they safe in severe weather?

In RLB’s last Crane Index study, Toronto had well over 100 cranes in use — the most in North America — with Calgary having over 30 of them dotting its skyline.

They’re a common, everyday sight for many Canadians. But as Haligonians witnessed when hurricane Dorian hit in September 2019, cranes can quickly deliver destructive force, if they fail.

“Wind is clearly the number one culprit,” says Doug Perovic, a University of Toronto engineering professor.

Perovic said that in an urban environment, there are several factors at play.

“You can also get wind events between buildings and there are various effects, there’s downdraft effects, the venturi or tunneling effect which gets accelerated through narrow spaces,” he said.

What often catches people’s attention on the ground during a wind storm is when they look up and see tower cranes “weathervaning” — that’s when cranes seem to be spinning uncontrollably.

But that’s normal, according to Global News meteorologist Ross Hull. It’s part of the plan to keep the structures intact during severe weather,

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