With the wildfires causing the evacuation of Fort McMurray there is talk of the possible effect of climate change on the current hot and dry weather conditions in Alberta. The chart above showing the monthly high and low extreme temperatures for Calgary going back to 1890 and current through this month doesn’t show any particular warming trend. However, temperature in Calgary is relatively high at present according to the season. Here is the daily record for the last few years, current through May 4th:
Another big factor is recent precipitation totals. Here’s a chart of precipitation from 1890 to present:
No glaring trend pattern there. Current conditions are very dry as the following zoomed-in view shows:
The daily precipitation totals give more detail:
So yes, current weather conditions there are hot and dry, but individually not so much out of the ordinary.
Perhaps a combination of the factors could reveal a trend caused by climate change. I.e., maybe the combination of hot and dry conditions is unusual. To that end, define a rudimentary “fire index” as the monthly high temperature in degrees C divided by the monthly total precipitation in mm. The units are arbitrary but give a measure of the relative fire danger. E.g, as temperature goes up and/or the precipitation goes down, the index goes up. Here’s the result 1890 to present:
So by that measure the current fire danger is the highest since 1890, and there does indeed seem to be an increasing trend over the years, perhaps due to climate change.