May 21, 2023 - Science

Smoke from Canada's wildfires prompts air quality alerts across U.S.

A satellite image of smoke from Canada's wildfires, which are impacting northern U.S. states.

A satellite image of smoke from Canada's wildfires that was impacting multiple U.S. states over the weekend. Photo: CIRA

Smoke from Canada's wildfires has drifted across the border and prompted air quality alerts across multiple U.S. states over the weekend.

Why it matters: Wildfire smoke poses a threat to people's health even when hundreds of miles from the fire sites because of its harmful microscopic particles, studies show.

Threat level: States including Colorado, Utah, Montana and Idaho issued air quality alerts and advisories due to the dozens of fires burning across western Canada over the weekend.

A screenshot of an NWS Sioux Falls tweet of a smoky sky saying: "A mainly blue sky to start the day today in our area but webcam images from northwest South Dakota (near Coal Springs) show that a murkier looking sky is expected by later today as thicker upper level wildfire smoke pivots southeastward once again."
Photo: National Weather Service Sioux Falls/South Dakota Department of Transportation/Twitter

State of play: Nearly all of Montana was affected by the smoke Sunday and hazy conditions were expected to continue through Monday. The National Weather Service's Glasgow, Montana, office recommended people with respiratory illnesses remain indoors and urged drivers to take precautions.

  • Colorado's Department of Public Health and Environment noted that while air quality conditions had improved across much of the east of the state on Sunday, "another plume of wildfire smoke is approaching" from the north.
  • Utah's Department of Environmental Quality warned air quality would remain "unhealthy for sensitive groups" through Monday.

Meanwhile, smoky conditions remained in parts of North Dakota Sunday and the NWS' office in Sioux Falls, South Dakota, forecast "plenty of high-altitude smoke" would linger across the region through Tuesday.

Context: Studies show that climate change is leading to larger, more intense and frequent wildfires.

The bottom line: Smoke will continue to impact the northern tier of the U.S. as Canada deals with a wildfire crisis that is setting it up for a long and damaging season.

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