At noon on May 3, the fire chief in the oil town of Fort McMurray was on TV telling everyone that the situation was in hand and they should stay at work and school and go to little league or whatever as usual. He had been watching the fire for a couple of days, but business as usual was what they did in Alberta in the spring; it was wildfire season, after all. At 2:05 evacuation orders started to come through. By 10 that night, much of the city that was not yet incinerated was burning.

The combination of extreme, record-breakingly high temperatures (91° F) with extreme, record-breakingly low humidity (15 percent), wind, and tons of dry fuel made for perfect fire weather. While this explosive combination used to be unattainable, it is occurring with growing frequency around the globe, including in areas that never experienced wildfires before.