Welcome to our ultimate Canadian flood guide!
Here, we cover important topics related to Canada's historical flood situations, the current flood landscape, municipal preparedness and economic implications.
Feel free to dig in & jump to whatever topic interests you:
March 22, 2020
Floods have been around for thousands of years, all the way back to the earliest civilizations. For example, there was Mesopotamia in the Tigris and Euphrates river valley, and Egypt in the Nile River valley. Floods were an integral part of life in these areas, as they deposited fertile silt on the river banks, and irrigated and enriched crops. The resulting effect of this was an increase in crop yield and more land for farming.
However, post World War II, flooding began to take a serious economic toll.
In an article in Procedia Economics and Finance, professor Dobrovic writes, " Since the early 20th century to the present day, there is a significant increase in the extent of damage caused by natural disasters. Only for the period since World War II has the total average amount of damage per decade increased almost tenfold."
The reasons for this were primarily due to the increase in urbanization and residential zones in flood-prone lowlands. Fortunately, mankind's technology improved and we found ways to stem the tide of flooding...to an extent.
Flooding is part of Canada's natural environmental process.
Historically, flood disasters have been caused by snowmelt runoff, storm-rainfall and flash flooding, ice jams, natural dams, coastal flooding, storm surges, hurricanes and tsunamis.
Between 1900 and 2020 there has been over 250 flood disasters in Canada.
More recently, urban flooding can be caused by stormwater runoff, riverine flooding and structural failure when engineered flood management structures, including dams and levees, prove inadequate to manage the quantities and force of flood waters.
Currently, damages related to flooding are increasing due to several theoretical causes, one being climate change, and the other being population increase and urbanization.
The effects of flooding are numerous. The Hamburg University of Technology gives a great overview of the effects of flooding, from the immediate to the long-term effects.
The immediate effects relate to loss of property and life. "Immediate impacts of flooding include loss of human life, damage to property, destruction of crops, loss of livestock, non-functioning of infrastructure facilities and deterioration of health condition owing to waterborne diseases."
Nearly every province in Canada has been deeply impacted by severe flooding.
Here are 5 of Canada's worst instances of flooding:
The Red River flood was the result of heavy snowfall & extreme temperatures and affected the Red River areas across Canada and the United States.
The City of Winnipeg, Manitoba, was hit the hardest, causing $500 million in damage to property and infrastructure and evacuating 28,000 people from their homes.
With cresting of 21.6 ft (6.6 m), the flood water approached Winnipeg at a speed of 138,000 cbf/ second (equivalent to the amount of water in an Olympic-sized swimming pool every second).
Citizens in Winnipeg were faced with 4.5 meter deep floodwater, which resulted in 60,000 people having to evacuate their homes.
With only a single fatality, Winnipeg's flood of 1950 cost the city about $126 million dollars (adjusted for 2020).
The 2009 flood was the second worst in Manitoba's history since 1826.
Heavy rainfall in combination with already over saturated soils from the previous winter, caused massive overland flooding.
To make things worse, ice jams raised the Red River to record levels (just barely lower than the record height set in the Winnipeg flood of 1997).
Caused by above-average precipitation in Western Manitoba and Saskatchewan, the Assiniboine River flood was classified as a 300-year flood (meaning it occurs once every 300 years).
While the last three floods in this article were caused by the Red River, the Assiniboine river caused the most severe flooding in 2011, reaching its highest level since 1923.
In some areas, the river was about 30 times wider and several meters higher than normal and caused the province of Manitoba to announce a province-wide state of emergency.
Heavy rainfall combined with the melting snow-pack of the Rocky mountains caused one of Canada's fastest instances of flooding in recorded history.
Affecting several southern-Albertan municipalities, the City of Calgary was hit hardest, with an estimated $6 billion in damages and five lives lost.
It took years for the city to rebuild essential infrastructure and for many businesses to recover from losses.
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Canada's flood-prone history is large in part due to rapid changes in water levels of lakes, rivers and coastal oceans. However, central provinces, such as Alberta, are greatly affected by snow-melt and storm water flooding.
By understanding and identifying the causes of Canadian flooding, citizens can prepare for what scientists are saying is inevitable: a severe increase in the frequency of future flooding.
Here are 10 of the most common causes of overland flooding in Canada:
Heavy rainfall poses a huge flood risk for Canadian municipalities.
While municipal drainage infrastructure usually functions well, heavy rainfall can overwhelm these systems and cause mass overland flooding.
And, with Canada's history of prolonged heavy rainfall, its no surprise this is the main culprit for Canadian flooding.
Five of the worst floods in Canadian history were caused by over flow from notorious Red River in Manitoba.
Adding to the case, BC experiences flooding from rising water levels of the Fraser River, and some of the worst floods in Alberta's history has been caused by the Oldman River.
Canada is famous for its long, harsh winters.
Unfortunately, this is the perfect recipe for spring flooding.
All that snow and ice have to go somewhere, and usually the resulting run-off goes to low-lying areas around the mountainous areas. .
Canada's large urban centers are huge paved sprawls.
As expected, pavement isn't very permeable, meaning floodwater wont be absorbed by the ground and needs to flow into drainage basins.
When municipal drainage basins over-fill, municipal flooding occurs.
Unfortunate geographical location plays a huge factor in flooding, especially in Canada.
In many provinces, governments are now putting restrictions on building in flood plains and food-prone areas.
Municipalities located near rivers, lakes, oceans, river bottoms and low lying plains are especially at risk.
Flooding can occur from fast runoff into lakes, rivers, dugouts and reservoirs.
This is often the case with rivers and other channels that feature steep sides, and the resulting rapid rising water-levels can cause severe overland flooding.
Vegetation is crucial for slowing runoff and preventing flooding.
With the absence of vegetation, there is a much higher chance that heavy rainfall and rising water levels will cause overland flooding. .
Soil can only absorb so much water before it becomes over saturated.
Once this occurs, the water (in many cases) has nowhere else to go and begins to pool. This is commonly seen on farmland during heavy rainfall.
Mountains or steep hills can increase flooding for low-lying municipalities.
Both rain and snow melt can rapidly ascend from mountainous terrain and quickly overwhelm sewage and drainage systems.
We've given you 10 common causes of flooding in Canada ...
Floods are the costliest natural disater in Canada and they can occur at any time of the year. Whether caused by rapid snow-melt, heavy rainfall or rising rivers, floodwater damages have cost Canadian municipalities billions of dollars annually.
Calgary experienced the worst recorded flooding in Canadian history.
During the 2013 flooding, over 122,000 Calgarians were forced from their homes, the city incurred billions of dollars in damages and the post-flood cleanup took years.
While remaining relatively flood-free for the last 6 years, researchers predict that Calgary still faces a 30% chance of experiencing an even greater flood before 2050.
Montreal's historic ice-storm flooding has been some of the worst in recorded history, the severity of which hasn’t been seen for generations.
In 2015, over 150,000 homes were left without electricity for several days due to mass floods.
Winnipeg is notorious for it's freezing cold winter temperatures.
In 2014, Winnipeg experienced the coldest winter on record since the 1800's.
Yearly thaw-cycles pose serious flood problems for the citizens of Winnipeg.
It's geographical location puts Halifax at a high risk for hurricanes.
Most recently, Hurricane Dorian touched down in Nova Scotia in 2019 and the resulting floods left more than 207,000 people without power.
St. Johns, NL
Canada is no stranger to heavy snowfall.
However, blizzards in St.John's create somewhat unmanageable flooding once the snow thaws.
Because of this, St. John's has consistently been a flood-prone city in Canada
Wondering which Canadian cities are best prepared for flooding?
Over the years, hundreds of thousands of Canadians have been affected by floods and with the rising global warming threat, it shows no signs of respite.
Water damage to the house caused by flooding can turn out to be an extremely expensive affair to the homeowners.
The Insurance Bureau of Canada has estimated that it would cost an average of $43,000 to repair a flooded basement.
In this article, we address what kind of repairs and restoration homeowners can expect after a flood and how much is that likely to cost them?
For an average house size of 2500 sq. ft, homeowners can expect to incur anywhere between $34,000 - $50,000.
In order to understand the extent of damage, homeowners may need to inspect three sets of cost:
Cost of clean-up
Without proper precautions in place during a flood, there is a high possibility that water floods the basement which would require a proper clean-up by professionals. It would require pumping out the basement using vacuums and suction followed by drying the basement using specialized ventilation systems. If this process is not done properly, water could seep into every space and cracks leading to mold infestation.
The cost of cleaning the basement could range anywhere between $7 and $10 per sq. ft.
depending on the extent of damage, size of the area damaged etc.
Since the drywall is porous, when exposed to water it can lose structural integrity. If
left untreated, the drywall might deteriorate over time and slowly sag, thus requiring
replacement. The paper backing the drywall can even become a perfect habitat for mold or mildew.
Depending on the extent of the damage after the flood, it may require restoration or
replacement. The cost of replacing drywall could be $2 per sq. ft. with hourly labor rate of $50 to $75.
If the basement and house has not been dried thoroughly, there is a high
chance of mold or mildew infestation as mold grows quickly aided by damp environment
affecting the structure of the building and the health of you and your family.
The cost of mold remediation depends on the size and the location of the mold infestation.
For small areas of the house such as crawlspace it could cost anywhere between $500 - $3,000 and for complicated areas such as wall ducts or attics, the cost can run north of $4,000.
Whether hardwood floor requires repair or replacement depends on the
severity and duration of water exposure after the flood. If hardwood floor is submerged in
standing water, it most likely would require replacement.
Hardwood floors are typically priced between $7 to $10 per sq. ft. plus labor costs.
If the damage is severe enough to warrant hardwood floors replacement, then the
carpets will need to be replaced too and it is estimated to cost approximately $4.7/sq. ft.
In addition to the above repair and replacement, homeowners have to bear the cost of replacing personal properties such as equipment, furniture and appliances.
While not everything might require replacement after the flood, some areas of the house such as ceilings and walls can most likely be repaired but hardwood floors and carpet may require replacement.
The best way to mitigate the risk is to be prepared with an effective flood protection barrier.
Flooding is the costliest and most common natural disaster affecting Canadians today.
As such, city resiliency efforts are immensely important for protecting Canadians and minimizing damage city property.
A 2015 study by Dr. Blair Feltmate from the Faculty of Environment at the University of Waterloo examined 15 flood-prone cities in an effort to gauge their resiliency towards flooding caused by extreme rainfall.
What factors were used for rate each city?
In addition, this study also utilized the findings of two previous research papers: a 2013 study that assessed the viability of overland flood insurance, and a 2014 study that examined priorities for advancing flood resiliency.
The results of the study?
Overall city scores for flood preparedness:
What are Canadian cities doing correctly?
The study found that most Canadian cities mandate the installation of backwater valves for new home construction – an effective step to prevent water from entering a house through the basement drain when sewer systems become overwhelmed by storm water.
Another area of strength was the development of up-to-date flood plain maps. Land use planners are using these maps to restrict building in flood prone areas and improve drainage systems in flood-prone residential areas.
Urban drainage maintenance was also a strength, as many municipalities ensure the functionality of culverts, grates and storm sewer systems.
This report provides a benchmark in which other cities can use to gauge their own flood resiliency efforts, identity areas in need of improvement, and ultimately increase their resiliency against Canadian flooding.
More on these findings can found here
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Canadian flooding causes billions of dollars in annual damages, with research showing that the frequency and intensity of floods will continue to increase.
Precautions must be taken to protect our homes, infrastructures, and roads.
In this section, we’ll explain why global warming is important, how it's affecting Canadian flooding, and what you can do to prepare for it.
Canada is warming up faster than the rest of the world, according to Canada's changing climate report.
While small incremental changes to the Earth’s temperature may not seem like a lot, it poses a higher risk than we think.
Our future is on the front lines of global warming; urging us to make smarter choices to preserve our environment.
Between 1948 and 2016, Canada experienced an annual temperature increase is 1.7 degrees Celsius as a whole, and 2.3 degrees Celsius for Northern Canada.
Increases in temperature fuels the rise of sea levels; thus increasing the risk of flooding.
In fact, at the time of writing this article (April 2020), 15,000 people in Canada are currently evacuating their homes due to rising rivers caused by ice jams.
Homes and roads are destroyed leaving people boating to find shelter and searching for lost pets.
Extensive rainfall has also been linked to the increased hurricanes caused by Global Warming, further contributing to flood situations.
Simply put, both Canada's government and its citizens need to take greater proactive initiatives to combat the increasing prevalence of flooding.
And, according this infographic, flood damages are only going to get worse.
This means failure to adapt will result in further billions of dollars in damages for Canadian residents, government and insurance providers.
While there are several options to take proactive measures, here are the top four suggestions to help you prepare for flooding caused by Global Warming:
Society must take extra measures in order to preserve the environment not only for themselves, but for the entire ecosystem and the future of upcoming generations.
Melting glaciers and rising temperatures are the major sources of intense flooding in Canada.
A warmer atmosphere holds more moisture which leads to an increase volume of rainfall.
This results in excessive rainfall that cannot be stored into land, inundation of waterways, and high tides, all of which contribute to the worsening annual flood problems that Canadians continue to face.