Connecting the Dots on Climate Data - 100 year storms not increasing

toronto weather
Connecting the dots on climate change. Real dots.
The report released today by the Environmental Commissioner of Ontario indicates "But now “1-in-100 year” storms, which are often the threshold for resilient design, are happening more frequently than in the past."  Well, no data supports that statement.

The graph above has some dots to connect as well - it is real data unlike the Environmental Commissioner of Ontario's infographic non-data, non-science, non-anything useful to anyone:

Connecting the dots on climate change. Fake dots .. fake like Jenny McCarthy anti-vaccine science.
We see the real Toronto rainfall volumes going down over a range of durations from 5 minutes to 24 hours.

But the Environmental Commissioner of Ontario's infographic has something cyan increasing .. but there are no labels on the axes ... is it real data ... is it past trends? ... is it future predictions? ... is it useful at all to anyone?  That yellow sign and exclamation point can't be good though! Actually this non-data is useless to anyone involved in urban flood mitigation, infrastructure planning and design, municipal design, floodplain mapping, insurance risk assessment, etc.

The most-reported anecdote of 100 year storms happening all the time is North York (north Toronto). This is often repeated by non-science commentators (but not practitioners). But still the plural of anecdote is not data, nor is it actionable.  If North York did get eight 100 year storms in 12 years then someone should have checked the extreme value distribution when they started counting 100 year events, because pretty soon you have to shift your frequency curves up after a few storms, and stop under-reporting the underlying frequency distribution over and over and over.

Here is real North York data at Environment Canada station 615S001 (a composite data record station so its not really one place at all):


North York is a shorter record and so less reliable on trends than the longer term Toronto City station 6158355 records that had higher rainfall amounts in the 1940's to early 1960's.  Yes there are some upward trends, but like a good scientist, statistician or engineer would do, look at the scale and consider the underlying variability / uncertainty in the data and you will conclude like Environment Canada has done already that there are no consistent or significant trends in rainfall frequency in Ontario or Canada.

The anecdotal North York 100 year storm epidemic is a convenient anecdote for former North York council (pre Toronto amaglamation) and their former planners and engineers, explaining the chronic flooding in a drainage system designed with no major, overland flow outlet, and that has been the topic of engineering study since the late 1980's.  If this chronically flooded North York area with all those 100 year storms (i.e., Toronto's Class EA Basement Flooding Area 28) sounds familiar, is it because physically it is a lot like the south Stratford area along Brydges Street - Elgin Crescent (catchment B23), where the class action lawsuit against the City was won.  That Stratford area also had back to back 100 year storms at the turn of the millennium.  Here is how that Stratford area with all the storms was described in the Beacon Herald 10-years-after-stratfords-watershed-moment:

"On Elgin Crescent we've been dealing with the problem for 20 years," complained Tom Arnott, who suggested the city had shortchanged residents in the southeast end of town.

Frank McLaren said the city should be giving everyone $1,000 to clean up their basements. He told "The Beacon Herald" at the time he was facing a cost of about $35,000 for the third time in three years because of the sewer problem.

City curbside collection teams were busy working extra shifts to clean up debris. Phones were ringing at insurance company offices. And angry citizens who had warned before of the need to do something about the city's aging storm and sanitary sewers began organizing.

The initial outcome was a class action against the municipality that sought more than $200 million in compensation for alleged negligence. That later morphed into a class action spearheaded by Mike Mitchell of the Mitchell Monteith law firm (later Monteith Ritsma Phillips) on behalf of about 800 residents who had experienced losses.

Resolution did not come easily. It was almost eight years after the flood - May 4, 2010 - when an out-of-court deal was reached between the City of Stratford and representatives of the claimants.

So was it a rash of 100 year storms, happening more often, that affected Stratford and contributed to them settling the lawsuit?  Or could it be that as the plaintiffs argued "the city knew about sewer problems and the potential for flooding, based on engineering reports, for three decades and did nothing about it."

Its funny how north Stratford, just on the other side of the Avon River, did not have chronic flooding when the Brydges-Elgin area did with their repeat 100 year storms.  Could it be the overland drainage patterns are better north of the river and there are better slopes?   Yes - as shown in the following paper (see Figures 4 and 7), the chronic flooding areas in Stratford were mostly explained by the topography, and the storms were a convenient excuse for chronic flooding issues:

Stratford drainage system review - American Water Resources Association - GIS Specialty Conference paper (Stratford Storm Master Plan, South Side Class EA)

The Environmental Commissioner of Ontario's report Connecting the Dots on Climate Data in Ontario does a great disservice to the discussion on rainfall trends and causes of flooding in Ontario. The quite worthless infographics and shunning of real actionable data on rainfall, and most disappointing, failure to explore any true causes of chronic flooding in Ontario municipalities, shows that the Commissioner's office is not up to the task of contributing to the important dialogue facing Ontario when it comes to addressing increasing flood damages and effective mitigation.

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Speaking of Straford : "Some are born great, some achieve greatness, and some have greatness thrust upon them." ... Shakespeare wrote that, but I think this could equally apply to "foolishness", i.e., some are born fools, some achieve foolishness, and others have it thrust upon them.  If you find value in the  Environmental Commissioner of Ontario's report Connecting the Dots on Climate Data in Ontario, then you may just fall into the last category.

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Now that Ontario has given us Connecting the Dots on Climate Data, what is next? Paint by Numbers on Health Care Reform, or Pin the Tail on The Energy Policy? Descartes gave us graphs to plot data in the 1600's - why can't the Ontario government use a few related to rainfall and present real data to build policy on?



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