Smoke from wildfires across Canada has blown into Colorado, causing smoky and hazy conditions that could last into the weekend, according to the National Weather Service in Pueblo.

The wildfires, which have burned more than 1 million acres in the provinces of British Columbia and Alberta, are casting heavy smoke across several U.S. states with moderate to heavy smoke possible across Colorado through at least Saturday morning, the alert said.

The Colorado Department of Public Health and Environment issued an air-quality health advisory for El Paso County and much of southern Colorado Friday afternoon through Saturday morning at 9 a.m.

Forecasters said Friday would be the worst day for the smoke, with gradual improvement possible over the weekend.

People are advised to limit outdoor activity in moderate to severe smoke conditions, especially those with heart disease or respiratory illness, or young children and the elderly.

The air quality is classified as unhealthy in Colorado Springs Friday evening and the forecast for Saturday is unhealthy for sensitive groups, according to AirNow.gov. Sunday and Monday are expected to have moderate air quality.

Colorado Springs saw a hazy Friday with light rain and fog, according to the Weather Service, with more rain and possible thunderstorms on the forecast for the weekend.