Why are Canadian wildfires affecting the U.S.?

Want to know a better term for "global warming?" "Global weirding." Freak snowstorms in Texas? Wildfires in Siberia?

And this past week, another wall of weirdness wafted over the Eastern U.S.: thick, smelly smoke from the 400 wildfires burning in Canada. Right now, about 11 million acres are on fire. That's bigger than Rhode Island, Connecticut, Delaware and New Jersey combined.

Two anomalies were at play simultaneously: First, Canadian wildfires that have burned 15 times more area than average; and winds that blew the smoke south, and then stalled.