charred

Canada’s 2023 wildfire season was the most destructive ever recorded. Over 6,000 fires burned nearly 71,000 square miles of land from the West Coast to the Atlantic provinces. The burned areas are roughly the size of the entire country of Finland and represent almost triple the amount burned in the previous year, which itself was a lot. Smoke from Canadian fires, particularly those in Quebec, blanketed many cities in the United States and made its way as far south as Florida.

An alarming aspect of the Canadian fire season is that it didn’t ever really end. Late in the winter, 149 active wildfires are still burning across Canada. 92 are in British Columbia, 56 in Alberta, and one in New Brunswick. In these places, the wildfire season is yearlong.

These overwintering fires have come to be known as zombie fires. They burn slowly below the surface during the winter. Many areas in the north contain porous peat and moss ground cover and these act as underground fuel for smoldering fires.

Wildfires have become more prevalent in Canada because the changing climate has brought about increases in the hot, dry, and gusty conditions that lead to drought.

Many of the zombie fires don’t pose an increased threat of triggering wildfires in the spring because they are in places that are already so charred that there is nothing left to burn. But others are in drought areas that are basically tinder boxes ready to burst into flame once spring arrives.

Overall, Canadian government officials are warning that this year’s wildfire season is likely to be even worse than last year’s, particularly in the Western provinces of British Columbia and Alberta.

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As ‘Zombie Fires’ Smolder, Canada Braces for Another Season of Flames

Photo, posted June 30, 2023, courtesy of P. McCabe / EU via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The worsening severity of wildfires across the globe is a major public health concern. The pulmonary and cardiovascular consequences of wildfire smoke inhalation have been well researched and have been an increasing focus for officials in places like California, other western states, and Australia. More recently, another public health concern has emerged related to the fact that wildfire smoke can carry microbes that cause infectious diseases.

A new analysis, published in the journal Science, points out that the risk of potential infection from airborne microbes has not been the subject of much research.

The fungus coccidioides, for example, becomes airborne when soils are disturbed by fire. When this fungus is inhaled, it can cause Valley fever, an infection with flu-like symptoms that sometimes progresses to pneumonia or meningitis. Inhalation risk of these microbes is highest closest to fires, so coccidioidomycosis is listed as a professional risk for firefighters.

A recent study found an increase in cases of invasive mold infection, aspergilliosis, as well as cases of coccidioidomycosis at hospitals within 200 miles of major wildfires in California.

Wildfire smoke has been shown to carry airborne particles of fungal and bacterial cells, hitching a ride on water vapor or charred carbon, over thousands of miles. Some microbes in soil appear to be tolerant of or even thrive under high temperatures following wildfires.

A multidisciplinary research collaboration is needed to better understand the relationship between microbes, wildfire, and public health. Such knowledge is increasingly vital as severe wildfires become seasonal norms in parts of the world such as the United States and Australia.

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Wildfire Smoke Can Carry Dangerous Microbes Thousands of Miles, Scientists Warn

Photo, posted September 9, 2020, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Canadian zombie fires

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Wildfire Smoke And Dangerous Microbes | Earth Wise

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