Essex County’s southern shore along Lake Erie was the scene of a tornado early in the morning of June 6. The violent storm tore up trees, shattered telephone and hydro polls, smashed cars and did so much damage to 10 homes they had to be condemned. It is only the latest example of violent storms that are becoming all too familiar in Ontario, especially near the waterfront. (Photo courtesy Gerald Mantha)

Climate change knocks weather forecasting for a loop
— unpredictable violent storms now the 'new normal'

News Archive BY GARY MAY
There’s no doubt in the minds of residents of the Essex County communities of Leamington, Kingsville, Colchester and Harrow who recently experienced a destructive tornado and violent downbursts: We’re getting more and more violent storms than ever before.  

It’s a belief that’s supported by David Phillips, senior climatologist with Environment Canada. The weather is less “normal” than it used to be, says Phillips.  

“I’ve been doing this job for 40 years,” Phillips tells, “and it’s been only in the last five years that I’ve reached the conclusion that the past is no longer a guide to the future.”  

That’s an observation that knocks the art of weather forecasting for a loop. Forecasting has always been based on studying what has happened in order to predict what is likely to happen. It’s a concept relied upon by farmers, city planners and designers, and even emergency planning experts.  

Windsor-Essex County hit hard

Essex County’s southern shore along Lake Erie was the scene of a tornado early in the morning of June 6. The violent storm tore up trees, shattered telephone and hydro polls, smashed cars and did so much damage to 10 homes they had to be condemned.  

Fish were seen flung onto a parking lot at the Leamington Marina and a man who lives in his 30-foot boat at that marina recounted a harrowing tale of being tossed around his vessel by the wind and waves. When he came up to survey the damage, the man was shocked to see several smaller vessels capsized and realized how lucky he had been.  

In nearby Windsor the night before, torrential rains flooded hundreds of basements while in the neighbouring states of Michigan and Ohio, more tornadoes struck. In Ohio, seven people died.  

Incredibly, no one was killed or seriously injured on the Ontario side of the border. But the fierce storms drummed home just how crazy — and unpredictable — our weather has become.  

Ontario’s weather is closely tied to the large bodies of water that surround the province. Storms can begin over the lakes and move inland. Those that come from farther away can intensify over the lakes, picking up moisture for a fresh assault.  

Some of Ontario’s worst storms — “storms of the century,” if you will — have picked up steam from the lakes.  

For example, Hurricane Hazel had travelled a very long distance when it rolled over Lake Ontario and met up with a powerful cold front. Blocked by a high pressure system to the east, Hazel stalled over Toronto, and dumped a huge quantity of rain over a large area in a short period of time.  

Brampton was hardest hit with the rain, but it was in Toronto’s rivers and ravines where much of the damage occurred. Up to 200 millimetres of rain fell, causing rivers and streams to overflow into residential areas. A total of 81 people died in Ontario. Damage totalled $135 million, which in today’s terms translates to $1.1 billion.  

One eyewitness told of seeing a car begin to cross a flooded bridge over a river. Unbeknowned to the driver, the bridge deck had been washed out. The car plunged into the rushing river and was never recovered. Presumably the wreckage sits someplace at the bottom of Lake Ontario.  

But out of disaster came new hope, says Phillips. Housing was banished from floodplains and replaced by park space, so as to ensure that never again would homes be washed away in a torrent of water.  

Sometimes we talk of a one-in-100-year storm, which, according to the United States Geological Survey, is a storm that comes around once every 100 years.  In other words, there is a one-per-cent chance of a storm of that magnitude occurring in any given year.  

Back-to-back occurrences more common

Random odds being what they are, however, it is quite conceivable that you could experience a one-in-100-year storm one year, and turn around and experience another one the next year. Mother Nature doesn’t adhere to timetables.  

Phillips says that sort of thing is actually happening. “We’re seeing more back-to-back occurrences. Two wet summers, then two dry summers. In the last five to 10 years, I’ve come to expect the unexpected. Nothing’s normal anymore.”  

Two examples occurred in the summers of 2004 and 2005. In 2004, Peterborough was struck by a downpour that constituted “one of the wettest moments in Canadian history,” says Phillips. “It could be characterized as a one-in-200-year event.”  

The next year, Toronto was struck by a storm that dropped up to 180 millimetres of rain in 90 minutes, overwhelming the drainage system.  

Those events occurred just a few years after what has come to be known as the Great Ice Storm of January 1998. Eastern Ontario and Quebec were pounded by perhaps the most extreme and widespread ice storm in Canada’s history. The freezing rain halted vehicular, rail and air traffic and, at one time, forced three million people to go without electrical power, as ice-laden transmission towers collapsed. Many people were without phones as lines came down.  

A state of emergency was declared and damage claims topped $1 billion.  

Phillips characterizes it as perhaps a one-in-1,000-year storm. It was an example of what can happen when a storm system “stalls,” he says. “They had a two-year supply (of freezing rain) in five days.”  

Climate change to blame

The increased frequency of extreme and unpredictable weather is the result of climate change, Phillips adds. “When you warm up the world, you get more evaporation, more heat and stormier storms. There’s just more energy in the atmosphere.”  

What does that all mean?  

“I tell farmers, ‘don’t grow what your parents did. Look at the last five years as a guide,’ ” he says.  

In cities, politicians should be instructing planners, designers and engineers to build for stronger winds and heavier rains. Drainage and sewer systems should be built to handle more sudden downpours, and more roof gardens and park space should be built to replace some of the concrete that covers so much of our downtown core areas and hinders absorption.  

Yet Phillips knows that cities cannot be built to withstand every weather phenomenon. The expense would be astronomical. – June 2010