Flood Risk in Canada is Real
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Canada has the world’s largest coastline and a vast system of rivers. This makes the risk from flooding a serious threat to Canadian communities. However, the access to flood risk data is not easy. For some communities, it is just not available.
The challenge remains in finding, understanding and updating this information. We are working to provide open access to the existing flood risk records. We also have a page to explain concepts linked with floods and would encourage everyone to spend a minute to familiarize themselves with them. 
As our online mapping tool catches up to the existing data bank of flood risk maps, there will be gaps in the data. If flood risk for your community is not present on the mapping tool, we encourage you to reach out to your provincial database for flood risk maps. If your community is lacking flood risk mapping, kindly contact us and we may be able to offer a means of constructing such data.
Flooding probability and intensity inversely related. Less intense floods occur more frequently and are stated as a lower category in our system. Likewise, More intense floods occur less frequently and are stated as a higher category in our system.
Flood risk is stated in terms of Annual Exceedance Probability(AEP). A flood has the probability of occurrence of once every 10 years, will have a 10% AEP. Similarly, a flood that has the probability of occurrence once every 200 years, will have a 0.5% AEP. This translates into the categories used above. However, every year, flooding is possible. Infact, every year, any category of flood can happen. A low AEP flood is just as likely to happen in a given year than a high AEP flood. So a 1% AEP or category 4 flood event has a 1% probability to occur in a year. Over 30 years, however, there is a minimum 26% chance of this category 4 flood occuring.
CATEGORY
FLOOD EVENT
AEP
1
1 - 2 Year
100% - 50%
2
2 - 10 Year
50% - 10%
3
10 - 50 Year
10% - 2%
4
50 - 100 Year
2% - 1%
5
100 - 200 Year
1% - 0.5%
Hence, a floodplain is always at risk of flooding. In Canada, the floodplain of a 0.5% AEP flood event as the delineation of a flood plain. It is encouraged to keep infrastructure and permanent investment outside this zone. To check out our tools, click here.