Western Canada's heat wave is 'unprecedented.' Scientists say it will become more common with climate change

Smoky skies. Polluted air. Sweltering heat. 

During three of the past five summers, British Columbians have endured extreme weather events, rewriting a season long known for its mild, sunny forecasts. 

This week's historic heat wave, which unleashed punishing temperatures on the Pacific Northwest and is now moving eastward to Alberta, has brought the realities of climate change into even sharper relief.

Climate scientists are cautious about citing climate change as the cause of any specific weather event. But some say evidence suggests extreme events are intensifying and becoming more common because of global warming.

"I'm shocked by this," said Simon Donner, a professor of climatology at the University of British Columbia. 

"As a climate scientist, we expect to see more extreme heat waves going forward into the future because we're adding greenhouse gases to the atmosphere. But this is even beyond my expectations. To have a heat wave last this long and be this hot in Canada is completely unprecedented in history."

'It really feels like dangerous heat'

The village of Lytton in B.C.'s Interior shattered Canada's all-time weather record over three consecutive days, surpassing an eye-popping 49 C on Tuesday. B.C.s Fraser Valley recorded temperatures in the mid 40s. Vancouver, which usually benefits from cool ocean air, recorded an overnight low of 24 C on Monday night, the type of heat often felt in the tropics. 

"There's something that feels a bit different about this one and I can't quite put my finger on it," said Joseph Shea, a professor of environmental geomatics at the University of Northern British Columbia.

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