Toronto just saw record rainfall. Why wasn't it more prepared?

Storm chasers saw it coming, and Environment Canada's rainfall warning suggested a deluge was coming so why were so many people caught off guard by the powerful storm that hit Torontoon Tuesday?

And how are residents supposed to prepare for events like this?

David Phillips, senior climatologist with Environment Canada, says the expected rainfall amounts were there all along.

"It was a surprise in terms of the [fact] it was well forecasted and the amounts were there in the forecast. But when you actually see them falling in a city as huge as Toronto, it becomes really devastating," Phillips said in an interview with CBC News Network on Tuesday.

The record rainfall caused widespread power outages and shutdown several major traffic routes. At the height of the stormalmost100 millimetres of rainfellin some areas, Environment Canada says, surpassing the city's daily record set back in 1941.

Some 97.8 millimetres of rain fell at Pearson International Airport, while 83.6 millimetres fell on Toronto'sdowntown corein just a few hours. About 87 millimetres was recorded at Billy Bishop airport on Toronto's waterfront, accordingto preliminary figures from the federal department.

City manager Paul Johnson said the city will review what happenedTuesday to be better prepared infuture.

"I don't want people to feel we were unprepared. We were," Johnson said at a news conference Wednesday.

"However, the situation changed significantly and when that shifted, we needed to pivot to try and ensure the safety of the folks that were caught in the storm."

Johnson said the city has been fielding questions about its decisions in responding to the powerful storm, particularly when it comes to roadways.

"We always review every incident after, and we will be paying particular attention to how we can utilize data and evidence in a stronger way to look at what response we should take," he said.

A series of separate storms consecutively drenched the GTA, but particularly the city of Toronto. He saidthe system that brought the rainfall was "unique" from a meteorological perspective,Phillips said.

"There was a line of storms from London to the west part of Toronto that lined up like a parade, like jumbo jets on the airport tarmac. And there was storm on top of storm coming in one after the other, dropping their load of precipitation," he said Tuesday.

A rainfall warning was issued for the city on Tuesday morning, with a risk of thunderstorms continuing in the afternoon and evening. The rain fell on Toronto in a four-hour window, but major traffic and transit disruptions persisted in the aftermath.

It has already been an unusually wet spring and summer in much of the GTA. From April 1 until Tuesday, the region was drenched in roughly 166 per cent of the rainfall it would typically see in that same period, Phillips said.

"That's a lot of rain. The grounds are saturated, the river courses are full."

Up to 110 millimetres of rain was initially expected to fall on Tuesday, withrainfall rates of 40 mm/hpossible at some points, the federal weather agency said.

Roughly 167,000 Toronto Hydro customers were without power at the peak of Tuesday's outages,the utility said.

Mark Robinson, a storm chaser and meteorologist with the Weather Network, said the powerful storm brought in a huge amount of rain in a short period of time.

"We were expecting some significant amounts of rain. But when it hits an urban area, that's the big issue," Robinson told CBC News Network on Tuesday.

"Not only did the first line of storms hit the GTA, the whole conveyor belt of moisture behind that, brought that rain in."

Robinson said summer thunderstorms are "some of the most difficult storms" to anticipate due to the unexpected amount of rain they canproduce.

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