Alberta’s 2023 wildfires: context, factors and futures

Abstract

Wildfires burned an estimated 2.2 million hectares in Alberta in 2023. We describe key attributes of the fires relative to historical fires and fire seasons and offer a perspective on potentially influential factors. Thirty-six large fires ≥ 10,000 ha generated 95% of annual area burned. Individually, these fires exhibited sizes, fire weather, and behaviour consistent with historical fires; there were simply far more of them in 2023. Thirteen fires reported in early May were ignited by lightning and reached final sizes ≥ 10,000 ha, revealing a previously unrecognized threat. Historically, large lightning-ignited fires reported before mid-May occur just once per decade on average. Collectively, 18 large fires reported in early May coincided with drier conditions compared with 18 large fires reported after mid-May. Early May fire weather was also warmer and drier than historical weather. The early May fire group was a temporally concentrated outbreak in west-central Alberta and coincided with extreme potential rate of fire spread. Large fires reported after mid-May were intermittent through to September, concentrated in northern regions and coincided with extreme potential for fuel consumption. Individually, these two spatiotemporal modes of fire season severity (outbreak, intermittent) produced annual burned areas on par with historical extremes. Together, the 2023 multi-modal pattern of fire season severity amplified area burned far above anything previously recorded. Potential contributing factors include climate warming, hemispheric teleconnections, phenology and exhaustion of suppression resources. Implications for future fire seasons, research and management are discussed