REGIONAL— Wildfire smoke and its potential health implications have become an increasingly important consideration when it comes to outdoor activities here in the North Country. But how to plan for the seemingly unpredictable incursions of wildfire smoke into the region can be a challenge.
Fortunately, there is an app for that. It’s the AirNow app, created by the Environmental Protection Agency, which has become a quick and easy go-to for current air quality measurements and three-day forecasts.
Air quality is measured by an index, known as the Air Quality Index, or AQI, based on a number of criteria. Index readings below 50 are considered good, readings from 50-100 are considered moderate, while readings from 100-150 are considered unhealthy for sensitive groups. AQI readings from 150-200 are classified as unhealthy for all groups, while readings from 201-300 are considered very unhealthy. Any reading over 300 is considered hazardous, which is a level that some parts of northern Minnesota have experienced several times already this summer. Back in May, Grand Marais set a new record for Minnesota with an AQI of over 800.
This past weekend, AQI readings across much of the region were over 200 at times, conditions which lingered into Monday before improving on Tuesday.
While the AirNow app was created by the federal EPA, in Minnesota it relies heavily on monitoring done by the Minnesota Pollution Control Agency, with a forecasting assist from MPCA meteorologists, like David Brown, who works extensively on smoke forecasting.
As with most summers, the wildfire smoke most commonly affecting northeastern Minnesota drifts in from western Canada. But a northwest wind isn’t the only factor that can bring Canadian smoke into the region.
According to Brown, there’s several factors that the MPCA tracks to make its smoke predictions. “There’s a few pieces to it,” he said. “We need to have an active weather pattern, like a cold front that brings the smoke down to ground level.”
Cold fronts typically prompt upper air to sink, which is what brings the smoke down to ground level where we all breathe it. “If we have a warm pattern, like a ridge of high pressure, the systems can go up and over it,” he said. These ridges of high pressure can act like a dome, which can keep the smoke up high in the atmosphere, allowing for better conditions here on the ground.
Brown notes that how actively fires are burning in Canada is another major factor. He notes that the dense smoke incursions our area experienced in May coincided with large and explosive fires, first in Manitoba, and later in northwestern Ontario, near Lake of the Woods. These fires encompassed hundreds of thousands of acres and were burning relatively close to Minnesota, pumping large amounts of smoke into the state.
Wetter and cooler conditions that settled into our region and points north in June helped to reduce the fire activity in Canada and improved air quality for much of the month.
New fires in Saskatchewan and Manitoba have broken out more recently after a wave of thunderstorms started numerous lightning fires. The warmer, dryer weather that followed those outbreaks have allowed these new fires to grow and they have been responsible for much of the smoke we’ve experienced in recent days.
Currently, more than 25 large fires are burning out of control in northern Saskatchewan, where the fire danger has reached high-to-extreme levels in many areas. Those conditions suggest that northeastern Minnesota can continue to expect worrisome levels of wildfire smoke periodically through the rest of the summer and likely into the fall.
While meteorologists can frequently make reasonably reliable forecasts out ten days, Brown said smoke forecasting isn’t quite there yet because there are so many factors that can play into the movements of smoke.
But if there’s one thing we can say with confidence, it’s that smoky skies will be a significant part of North Country summers for the foreseeable future.