Smoke from U.S. wildfires spreads to at least 5 Canadian provinces

Smoke from uncontrolled wildfires along the U.S. West Coast is blowing eastward, stretching thousands of kilometres across Canada and covering several provinces. 

Dozens of blazes have raged with unprecedented scope across some 18,000 square kilometres in Oregon, California and Washington state since August, laying waste to several small towns, destroying thousands of homes and killing at least 36 people.

The fires also have filled the region's air with harmful levels of smoke and soot, bathing skies in eerie tones of orange and sepia while adding to a public health crisis already posed by the coronavirus pandemic. 

That smoke was seen sweeping eastward Tuesday, with it blowing as far as Toronto and Ottawa, as well as to the northeast, covering Alberta, according to satellite imagery captured by the U.S.-based National Weather Service (NWS). 

"Notice that the smoke originates across the west and then gets pulled to the east due to the jet stream aloft. The haziness may increase later today," NWS said.

On Monday smoke blanketed Vancouver so thickly that Canada Post was forced to stop deliveries for the day, calling the conditions "unsafe." While on Sunday, the union representing B.C. teachers urged the province to close schools, citing the combined threat of wildfire smoke, which is affecting air quality, and the COVID-19 pandemic.

"The combination of COVID-19 pandemic and extremely poor wildfire air quality is deeply concerning for #bced," the B.C. Teachers Federation (BCTF) said on Twitter. "Teachers and students should not be in crowded classes with no ventilation or fresh air."

Ten deaths have been confirmed during the past week in Oregon, the latest flashpoint in a larger summer outbreak of fires accompanied by catastrophic lightning storms, record-breaking heat waves and bouts of extreme winds in the U.S.