Smoke over downtown Calgary, AB, 14 August 2018 (Dearing)
Smoke from forest fires in British Columbia is streaming into Alberta resulting in poor air quality and reduced visibility.
Environment Canada says smoke conditions can change quickly during wildfires but air quality will be poor for the rest of the week.
Small children, seniors and anyone with chronic conditions are especially at risk.
British Columbia has declared a state of emergency with over 560 out-of-control wildfires forcing 3,000 residents from their homes and another 20,000 are under evacuation alert.
Helicopter drops water on eastern flank of Parry Sound 33 fire, 30 July 2018 (Ontario Ministry of Natural Resources)
A forest fire in northeastern Ontario is edging dangerously close to the Trans Canada Highway which links the northern and southern parts of the province.
Known as Parry Sound 33, the fire has burned more than 100 square kilometres since it began on 18 July and smoke has been creating poor air quality.
Many small communities, south of Greater Sudbury, are either being evacuated or are on alert to leave at a moment’s notice.
More than 600 firefighters from across North America have arrived to help battle this blaze and dozens of others across the region.
Forest fire smoke envelops Yellowknife, NWT, 16 August 2014 (Twitter)
More than 50 forest fires are currently listed as out of control in the Northwest Territories during what has become a summer of fires.
The blazes have scorched more than three million hectares of land and have created drifting smoke which has meant poor air quality in numerous communities including the capital of Yellowknife.
Smoke from the fires has also been carried southeastward by the jet stream to Ontario, Quebec and the Northeastern United States keeping daytime highs lower than normal.
Commercial fishermen also say the fires have dramatically raised temperatures in rivers and streams leading to a scarcity of fish.