Is Montreal safe from extreme flooding?
Extreme flooding – Given the reality of climate change and the extreme weather we have been experiencing here and globally, it makes one wonder how safe we are – especially from flooding on the Island of Montreal. There are many factors which give cause for concern.
The recent catastrophic rains in Texas were unprecedented and the images broadcast all over the world hit hard, particularly here after the historic and record-breaking flood last spring. How many of you would have ever imagined the Rivière des Prairies flowing up Saint-Jean Blvd. to Pierrefonds Blvd. and a man paddling his way in a canoe to Tim Hortons to order Timbits?
Global warming is not a myth – as the President south of our border seems to believe. In fact, it has become an unwelcome and undisputable reality. Climate change, a broader term, is proving that carbon pollution does more than just warm our planet – it is also changing rain and snow patterns and increasing the risk of intense storms and droughts. For example, just this summer while raging fires were burning in BC, a microburst storm ripped through the Montreal area.
It is not only effecting weather patterns, but also the rise in sea level – both at an alarming rate. Scientists from all over the world have been warning us for decades we have to make urgent changes, and we are only now starting to understand how serious that is.
The greatest indicator of global warming is the alarming rate at which the polar ice caps are melting. Data from a 2013 study, supported by NASA and European Space Agency ESA, showed that in just 20 years they melted faster than in the last 10,000 years. But more importantly, is how it translates into the rise in sea levels.
In 2014, global sea level was 2.6 inches above the 1993 average and the level continues to rise at a rate of about one-eighth of an inch per year. About 70% of the earth’s surface is covered in water and at the rate the sea level is rising, the 30% we live on has never been more vulnerable as it is right now – vulnerable to flooding and storm surges of epic proportions.
If all the ice covering the Antarctica and mountain glaciers around the world were to melt, sea level would rise about 70 meters (230 feet). Cities along coastlines would be covered and there would be a significant shrinking of land area. Depending on where you live and how high it is above sea-level, the threat can be great.
Let’s put it into perspective for the Montreal Island.
Montreal at its highest point on Mount Royal is 233 metres (764 feet) above sea level, but as you go down the mountain it begins to drop. Part of Outremont and Cote des Neiges is around 180 metres above sea level, but lower down it begins falling to approximately 166 to 154 metres – including a part of Westmount. With a 70 metre rise in sea level, those areas would still be dry.
After that is where it becomes apparent that if the sea level continues to rise at the rate it is now, areas from the east part of the island to the west end, standing at 38 to 96 metres above sea level, would be seriously threatened – including Hochelaga de Maisonneuve, Rosemont La Patrie, Anjou and St. Leonard, as well as NDG, Lower Westmount, Saint-Laurent, Montreal West, Hampstead, DDO, Cote St. Luc, and Kirkland. Parts of other areas closer to the edge of the island at only 19 to 38 metres above sea level, like in Pierrefonds/Roxboro, Dorval, Beaconsfield, Baie D’Urfe, Ste-Anne-de-Bellevue in the west and towards the east, Pointe Aux Trembles, Montreal North, St. Henri, Verdun, Little Burgundy, Griffintown and the Old Port area – would all be completely under water.
With all that said, it would still take the polar ice caps to completely melt – and hopefully actions will be taken and changes in the way we live will happen, well before we find Montreal’s Old Port relocated to Beaver Lake on top of the mountain.
Nevertheless, in the present, the reality of climate change is disconcerting. Closer to home, the spring flooding and the recent storm (best described as an upside-down tornado) hit the city. There was an actual tornado in Lachute just northwest of Montreal and parts of Ontario have been seeing funnels touch down there with regularity – including close to Ottawa.
It’s not just the rise in sea levels we should be concerned about – but in the present, it is also the extreme weather patterns and storm surges, of which meteorologists say will only increase in intensity and frequency.
On July 14th in 1987, more than 100 millimetres of rain fell in less than three hours during a storm, flooding the Decarie Expressway and many other roads. What would happen if the storm in Texas were to hit here? Hurricane Harry dropped up to 3 feet of rain in some areas – that is 900 millimetres, falling at 76 to 100 millimetres per hour. If that amount of rain fell in Montreal, the Decarie Expressway would have become Rivière Decarie.
Montreal is also far from flat. There are dips and ‘bowls’ all over the island, including underpasses and other infrastructure. One island could have turned into a thousand islands, rivalling those of Gananoque near Kingston, Ontario.
How many of you remember when in 2012, the storm surge from Hurricane Sandy in New York City flooded tunnels, submerged subways and destroyed homes?
Global warming and climate change is a challenge like no other faced by the human race. It is up to us and those we have chosen as our leaders, to make the changes urgently needed.
Are you prepared for more extreme weather? Do you feel Montreal is safe from extreme flooding? And the bigger question – can we survive our own progress?
Feature image: Pierrefonds Blvd and St. Jean blvd. completely under water from Spring 2017 flood