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Recently, I assembled data about droughts in Canada with the objective of using them in economic models. As I always do before using data, I plotted them to learn about trends, and to check for outliers and other possible problems. I found those charts interesting, and thought I should to share them with you.

I show in this post data from the Canadian Drought Monitor (CDM). Monitoring drought is not an easy task and I invite you to check CDM webpage for explanations about how droughts are measured. The table below shows the category system CDM uses. The categories represent the severity, spatial extent and impacts of the drought.

One thing CDM does not tell us is the moisture level when there is no drought. It could be that the conditions are perfect for farming but it could also be that in some regions fields are flooded and not in better shape than in a drought. This is a limitation of the CDM. Environment and Natural Resources Canada offers other measures of drought and moisture but I will not use these data here.

Drought maps

Agriculture and Agri-Food Canada (AAFC) publishes monthly a map that shows drought intensity across Canada. This is a great map that I frequently use during the growing season. However, as I’m interested in the impacts of drought on agriculture, I find it difficult to gauge how much farm land is affected by a drought. Below, I show in a map the extent that droughts affect farm land.

Note that monitoring drought over the entire territory it very relevant, especially to evaluate the risk of forest fire. My goal is, however, different as I seek to examine how droughts specifically affect agriculture.

Drought conditions for all Canada

The figure below reproduces the CDM map published by AAFC. I simplified the map by omitting to plot the impact labels and the impact lines that the AAFC map includes.

The map shows that a very significant part of Canada is under droughts of various intensities. The most intense drought region is Northern Alberta and the Northwest Territory. No region of Canada is an exceptional drought. The drought affects mostly northern regions where there is no agriculture. There are drought conditions in southern part of Canada but it is difficult to tell how much farm land is under drought.

Figure 1: Canadian drought monitor (August 31, 2024)

Drought conditions for farmland

The next map show CDM map but only for the agricultural ecumene, defined as the areas where the country’s main agricultural activities take place. I use the agricultural ecumene as a proxy for farm land. I added to the map, in green, the parts of the agricultural ecumene that are not under a drought. As pointed out earlier, the data do not tell us whether there is a surplus of moisture in these areas.

The maps give a better idea of how much farm land is under a drought. Southern Saskatchewan and Northern Alberta, and a good part of the agricultural ecumene in British Columbia are in moderate or severe drought conditions. In the East, north-east parts of the agricultural ecumene in Quebec are in moderate drought conditions.

Figure 2: Canadian drought monitor for agricultural farmland (August 31, 2024)

Droughts over time

What motivated me to collect drought data was to observe their frequencies. The following figures show by province the shares of the agricultural ecumene affected by drought conditions. The CDM data are only available since 2002, too short a period to determine whether climate change has made droughts more frequent and more intense.

I was surprised to find that there is a Wikipedia page about Drought in Canada. The page notes that the most serious drought was between 1999 and 2004 in the Prairies. Unfortunately, the CDM data do not allow us to fully observe that event.

Atlantic provinces

The agricultural ecumene in Atlantic provinces is small and meteorological events tend to affect the whole areas all at once. This is particularly obvious in Figure 3 for Prince Edward Island.

Atlantic provinces are not seriously affected by major drought events. The latest serious episode of drought was in 2020. Observe there were practically no drought before 2010.

Figure 3: Drought index over time in Atlantic provinces

Central Canada provinces

Quebec and Ontario are affected by episodes of drought, more frequently and more severely in Ontario. The most important drought was in 2007 and 2008 in Ontario. The data do not allow to identify episodes of excess moisture, which could be a more important problem than droughts in Quebec and Ontario.

Figure 4: Drought index over time in Central Canada provinces

Western Canada

Droughts are frequent and sometimes severe in Western Canada. Alberta and British Columbia are the driest provinces. The 2021-22 drought was widespread and intense with some areas under exceptional drought conditions. That drought seems to have never ended in Alberta, but Figure 4 does no allow us to observe whether it is the same areas that are continuously affected by drought conditions. British Columbia is under the worst drought conditions since the data begin in 2002. Large squats of the agricultural ecumene in Saskatchewan have stayed under drought conditions since 2001. Drought conditions returned to Manitoba in 2023 and 2024 but have recently disappeared as Figure 2 shows.

Figure 5: Drought index over time in Western provinces