The most dangerous forest fires will become twice as likely to break out into unstoppable infernos in the decades to come, a Canadian study published in the journal Environmental Research Letters predicts.
The findings by researchers from the Canadian Forest Service and the Universities of Alberta and Toronto hold a warning that the scores of fires which smothered the lower B.C. mainland in smoke earlier this summer, and the walls of flame that forced 80,000 residents of Fort McMurray from their homes last year, will become both more common and more dangerous. One member of the research team, wildland fire specialist Mike Flannigan, was involved in assessing the Fort Mac conflagration as it was under way.
Firefighters often consider “crown” fires—which race from treetop to treetop, advancing faster than crews can respond—the most dangerous form of wildfire breakout. The most alarming finding in the report may be that the number of days when those fires overwhelm all human suppression will more than double in parts of the northern and eastern Canadian boreal forest by the end of the century.
Populating well-established fire probability models with data from a variety of global climate models, the researchers found that future conditions imply “fireline intensit[ies] frequently exceeding thresholds beyond which even resources such as water bombers were [un]able to have an effect.”
Past studies have firmly established that warming trends will likely increase the frequency of forest fires, and that increasing evapotranspiration as result of warmer temperatures will more than offset increases in precipitation—leading to overall drier forests more primed for ignition. The latest research reveals that the “numbers of escaped [uncontrollable] fires increase disproportionately more than overall fire occurrence increases.”
In other words: not only do we face more fires in Canada’s vast forests, but those fires are up to twice as likely to be so big, so hot, and so fast that nothing in firefighters’ arsenal of suppression techniques will stop them.