The burning question

Photo credit: Landon Parenteau

Are wildfires more frequent than in the past?

An explosion of northern wildfires in June and July kindled great anxiety. Clouds of smoke blew over major U.S. cities in the Northeast and Midwest, and both Toronto and Montreal were smothered for several days. The sun sometimes appeared red when it wasn’t entirely obscured.

Public health alarms went off. Children and people with respiratory problems were urged to stay indoors, which shielded them from the worst effects on their lungs.

Alarmed TV viewers and Web surfers often got the impression this was all “unprecedented”, to repeat a ubiquitous adjective in the media. But were the Canadian forest fires of June-July 2023 truly exceptional over a longer time period?

Obscuring the horizon

The closer I looked, the less likely that seemed. Wildfires have been erupting for centuries. It is Nature’s way of clearing the ground of biological waste and preparing for new growth. And smoke from such fires has regularly wafted down over the cities of North America, often obscuring the horizon and even blocking the view along streets.

In a remarkable Bloomberg feature (July 1), writer Justin A. Fox recounted the great Boston blackout of 1780:

https://www.bloomberg.com/opinion/articles/2023-07-01/alarmed-by-smoke-new-englanders-of-1780-would-like-a-word

During that crisis, a Harvard professor reported that “the darkness was so great, that people were unable to read common print — determine the time of day by their clocks or watches — dine or manage their domestic business, without the light of candles”. May 19, 1780 was later dubbed New England’s Dark Day. It was traumatic for the population; many fervently believed it presaged the End Times.

Its cause? Smoke from wildfires blown in from northern Canada. The source of this smoke was later confirmed in tree rings in Ontario.

Adds Bloomberg: “Similar if less extreme occurrences in Massachusetts in October 1716 and August 1732, and in Detroit in October 1762, which couldn’t be explained by eclipses or volcanic eruptions … were thus probably due to wildfire smoke” from Canada.

The writer concludes: “Smoke from wildfires was a familiar feature of life in the U.S. through to the early 1900s ….  The relatively smoke-free second half of the 20th century was the anomaly”.

Wildfires in Canada, 1980-2021: area burned (dark bars) last peaked in 1989, then fell to a low in 2020. The 2023 season will be the overall peak. Source: CNFDB.

Deep haze on cities

In June 2023, with New York, Boston, Montreal and Toronto under a haze, news media often portrayed this as the product of an entirely new trend. But what does the Canadian forest-fire record of the last 40-plus years show?

The most authoritative source for wildfire data is the CNFDB, or Canadian National Fire database. Its 1980-2021 record (see graph) displays both the number of fires and the total area burned across Canada. The trend for fires was broadly downward for four decades. In 2023, obviously, that pattern was broken, at least for one season.

The year 1989 was the previous “peak fire” year both for total area burned (7-8 million hectares) and the number of fires (roughly 12,000). Other top burn years include 1981, 1994 and 1995. No season with such fire destruction was seen in the 21st century, until this summer.

The figures for 2023 wildfires (through to July) did indeed surpass that 1989 peak, with roughly 10 million hectares burnt, after an early fire season was set off by lightning in northern Quebec.

On July 11th, McGill held an online discussion of wildfires, with a panel that included an expert from its Department of Natural Resource Sciences, Benoît Côté. In emails later, Dr. Côté transmitted the federal government’s figures for hectares burnt by wildfires in Quebec over the last decade (2023 is pending).

For Quebec alone, the fire year 2013 “was the record year since 1990. The average of the last 10 years …  is approximately 45,000 hectares” a year consumed by fire, said Côté. The final results for 2023 will show if a new provincial peak (i.e. over 187,000 hectares) was reached.

California bounces back

During this crisis, I recalled that in November 2018, we had motored through California via the interior route rather than scenic Pacific Coast — driving northward from Bakersfield to Fresno and Modesto. The landscape in the heavily agricultural Central Valley was dusty and the sky was generally overcast: wildfires in northern California were blanketing much of the state with ash.

Once we arrived in the Bay Area through Berkeley, I saw for the first time (but not the last), people wearing masks in the streets. Many other people had left town for points south. Berkeley campus was quiet; a big college football game was cancelled. The smoke was winning.

Then a few days later, light rains started falling in San Francisco, and the ash clouds began to disperse. From then on, skies grew clearer.

Fast-forward to 2023, and much has changed. The town of Paradise in northern California, which was devastated by 2018 wildfires, has largely recovered. The fire disaster was terrible, but temporary. Disaster preparedness has been reinforced. The local population has doubled.

More important, weather conditions since 2018 have changed entirely. California and the Rocky Mountain West had a wet spring in 2023. Huge snowfalls left a deep snowpack that steadily melted, feeding Western watersheds. This has meant lots of runoff and rising water tables.

Salt Lake in Utah, which some forecast would just dry up after years of drought, has risen by 5 feet since spring 2023. More surprisingly, an “instant lake”, Lake Tulare, has suddenly emerged in the middle of the drought-parched San Joaquin Valley in California, flooding farmland, buildings and roads. At press time, Lake Tulare was 178 square miles and growing.

Nobody predicted these weather developments. So, when a media forecaster says they know what the 2023 wildfires in Quebec portend, it is worth asking: How do you know that?

First published in the Sherbrooke Record supplement, Townships Weekend, Aug. 5, 2023.