Triggers of the Record‐Breaking 2023 Canadian Wildfires: Extreme Heat Waves and Droughts Driven by Abnormally High Sea Surface Temperatures

The 2023 Canadian wildfires burnt the areas across the Northwest Territories and British Columbia during May–September with record‐breaking intensity. However, the near‐surface meteorological conditions, atmospheric circulation, and climate drivers behind these exceptional events remain insufficiently understood. Using multisource data sets, dynamic diagnostics, and numerical modeling, this study identified unprecedented 2023 heat waves and droughts in wildfire‐prone regions as key contributors to the wildfire severity. These extreme conditions were closely associated with abnormally high sea surface temperatures (SSTs) in the northwestern North Pacific (NWNP) in 2023. Acting as a strong heat source, the elevated SSTs triggered a Rossby wave train that mainly propagated southeastward across the North Pacific and then northeastward into North America. This wave activity contributed to the weakest upper‐level westerly over central North America and the strongest high‐pressure ridge over northwestern Canada in 2023, thereby facilitating the favorable near‐surface fire weather. As NWNP SSTs continue to rise, their influence on wildfire activity in northwestern Canada is expected to grow. Our findings highlight the critical role of sea‐atmosphere interactions in wildfire behavior.