Normally frigid prairie cities are into their second week of a January thaw that has seen overnight rain in Edmonton and shirt sleeves in Calgary.
Climate scientists blame the jet stream.
The fast, high-altitude river of air normally moves smoothly from west to east but has become increasingly loopy in recent years.
David Phillips of Environment Canada says the jet stream, which normally flows over the middle of North America, is now drooping as far south as Texas.
He says that’s bringing warm air to places that are normally cold and cold air to warm regions — and those disruptions are sticking around for days and weeks instead of moving on.
Jim Byrne, a climatologist at the University of Lethbridge, says it’s consistent with a theory that suggests the wandering jet stream is caused by shrinking Arctic sea ice.
