Less than two weeks after floods swept through southern Alberta, Toronto was also deluged. On July 8, 2013 an astounding 126 mm of rain fell on the city within two hours during the evening commute. 300 000 residents lost power, and there was flooding on several downtown streets that submerged cars and basements. A large portion of the Yonge-University-Spadina subway line was also flooded and put out of commission. The most spectacular incident was likely when the flooding trapped a GO train on the track and the subsequent rescue of its passengers in small inflatable boats.
However, there were no mass evacuations or homelessness, as occurred due to the flooding in Alberta. The flooding in Alberta was particularly extensive because it was caused by a combination of rain and spring meltwater from the mountains. This combination caused the rivers that ran through the affected communities to rip away flood walls and erode banks. In Toronto, the flooding was caused only by precipitation and the later overfilling of storm sewers.
Prior to July 8, 2013 the last major comparable rainfall in Toronto was during Hurricane Hazel in 1954. In this case 200 mm of rain fell, of which 121 mm fell over the course of 24 hours. During that flood, the Humber River overflowed and the neighbourhoods of Long Branch and Raymore Drive in Etobicoke were destroyed and consequently converted into parks.
Hurricane Hazel prompted the creation of the Toronto and Region Conservation Authority to implement floodplain regulations and the organization was also given purchase authority to manage the city’s floodplains and rivers. Hurricane Hazel, having exceeded the 100 year storm design conditions, also became the design standard for floodplain systems in Southern Ontario. Both Hurricane Hazel and the June flood were particularly devastating since the soil in Toronto had already been saturated by rain on previous days. However the flooding in 2013 was less devastating, there were no drowning-related deaths or widespread evacuations, whereas Hazel left 81 dead and 4000 families homeless. Less than 24 hours after the storm, the subways were in operation again, and most of the city was back to business, apart from some isolated power outages.
Interestingly, the Flood Damage Reduction Program was established in 1975, which allowed federal and provincial governments to share the costs of creating flood risk assessment and floodplain mapping. However, this program was dissolved in 1990, and since then flood-risk management has been neglected at the federal level. One wonders if it is time to revise the old floodplain data. Houses that were built above the flood line and previously safe may now be endangered by upstream development, which would have paved over green lands and decreased surface permeability. Furthermore, recent weather patterns should be taken into account: although precipitation may not be increasing, it is becoming more frequent, which could affect erosion and infrastructure deterioration.
Side note: Rob Ford was chilling with his kids in his air-conditioned SUV when the power went out. In contrast, the Calgary mayor, Naheed Nenshi, worked non-stop for 43 hours during the flood, appearing to never sleep and inspiring the hashtag #nap4nenshi, and Doug Ford (Rob Ford’s brother) was directing traffic in Etobicoke.
Leave a Reply