SARANAC LAKE — Smoke from wildfires burning in central and western Canada began moving into the skies over the Tri-Lakes region last night and is expected to increase throughout today before clearing out of the area later Wednesday.

Unlike some of the more potent local smoke events in 2023, this round is expected to mostly remain in the mid- and upper-levels of the atmosphere and away from ground-level, mitigating impacts on air quality. Still, it’s likely that some smoke will make its way closer to the surface later today, according to the National Weather Service’s Burlington, Vermont office, which serves the Tri-Lakes region. This could lead to a faint smoke smell at times and possibly lead to breathing issues for sensitive groups.

As of press time Monday evening, no air quality alerts had been issued by the state Department of Environmental Conservation, which is forecasting moderate air quality today with air quality index values between 51 and 100. The DEC typically issues those advisories when the AQI rises above 100, and the air is considered “unhealthy for sensitive groups.”

The AQI is calculated based the amount of the five major air pollutants regulated by the Clean Air Act in the air at a given time: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide and nitrogen dioxide, according to the NWS’s website, which noted that the various index severity levels and descriptions are based on established national air quality standards established by the Environmental Protection Agency.

NWS Burlington Meteorologist Maureen Hastings said today’s plume of smoke originated in the Canadian province of Manitoba and northwesterly winds helped to push it into the Tri-Lakes area. She said that most of it should stay higher up in the atmosphere — resulting in hazy-appearing skies.

“The bulk of it should stay aloft,” she said. “However … it does look like there’s going to be some near-surface smoke.”

Hastings said the smoke should move in higher in the atmosphere first, and possibly reach lower elevations as the day goes on, with the greatest chance of surface smoke — and subsequent impacts to people — expected this afternoon and evening. She said it would remain during the overnight hours before the wind changes to a southwesterly direction, moving the smoke out of the area and cutting the Tri-Lakes off from the smoke source.

Scott McKim — a meteorologist who serves as the science manager at the Atmospheric Sciences Research Center’s Whiteface Mountain Field Station — said the amount of time a plume of smoke spends in the atmosphere plays a key role in determining how much of it impacts air quality on the ground.

Known as “residency time,” McKim said the longer the smoke travels in the atmosphere, the less potent it generally tends to be at the ground level. One of the reasons the 2023 occurrences saw particularly dense smoke was that the source fires were in Quebec, considerably closer to the Tri-Lakes than the western provinces, giving the smoke a much shorter residency time.

McKim noted that residency time does not have a direct relationship with the distance between the fire and the area being impacted by the smoke. For instance, he said there was a plume of smoke over the Adirondacks on Monday that originated in Manitoba, but the winds carried it up toward the Arctic, then down into the Central Plains and Midwest before looping it back into the northeast. This elongated its residency time allowed the smoke to stay aloft by the time it got here.

The AQI remained in the “good” range, below 50, for the Tri-Lakes region during Monday, according to the DEC.

In contrast, McKim said today and Wednesday’s smoke comes from the same location, Manitoba, but the wind patterns have changed so it’s taking more of a “straight shot” of a path here from the source, resulting in the forecasted relative decrease in air quality.

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Conditions at the source

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Around the Tri-Lakes region, April and May had above-average rainfall, according to meteorological data gathered from the Adirondack Regional Airport. It’s been a different scene in central and western portions of Canada, where a dominant ridge of high pressure has resulted in above-average temperatures and dry conditions. This has created an environment that allows the fires to spread quickly and become difficult for firefighters to control.

“Kind of a perfect storm out there, of sorts,” McKim said. “And obviously very early in the fire season.”

While the weather conditions are largely responsible for the rate of spread and the acreage burned, the actual cause of ignition for most of the 2025 wildfires to date have been humans, according to Canadian government data. In Manitoba, 98 of the 106 fires to date have been started by humans, with four being attributed to natural causes, such as a lightning strike, and another four remaining under investigation as of press time Monday evening.

It’s unclear how this data correlates to the size or severity of these fires. Historically, fires with natural causes have tended to burn the largest areas as they are often ignited in extremely remote areas and firefighters often don’t realize the fire is burning until it has grown considerably — and is therefore harder to control.

About 2.67 million acres have burned so far this season across Canada, according to Canadian government data through May 30, with Manitoba and its western neighbor, Saskatchewan, experiencing the worst conditions. More statistics are available at cwfis.cfs.nrcan.gc.ca/report.