The Western Canadian city of Calgary received a special weather alert on Tuesday, warning residents of poor air quality and reduced visibility as tinder-dry weather and shifting winds elevated the risk of spreading wildfires in the oil-producing province of Alberta. Some 90 wildfires are active in Alberta, with 23 out of control, according to the provincial government, forcing about 20,000 people out of their homes. At one point the fires forced oil and gas producers to shut in at least 319,000 barrels of oil equivalent per day, or 3.7% of national production. On Tuesday morning, Calgary-based Crescent Point Energy said it was shutting in its Kaybob Duvernay productio...Keep on reading: Calgary air quality deteriorates as wildfires rage in Western Canada