There were about ~6,700 reported wildfire ignitions in 2023, which represents—surprisingly— a lower
number than the average of about 8,000 wildfires per year (Hanes et al. 2019). Lightning ignited 59% of
the wildfires and lightning-caused wildfires accounted for 93% of the total area burned (long-term
average = 91%) (Hanes et al. 2019). Lightning storms that caused multiple simultaneous ignitions that are
beyond initial attack capacity led to several large fires, some of which eventually coalesced. Lightning
fires that started on four days, May 13th, May 27th , June 1st and July 5th, were responsible for 30% of
the total annual area burned. Interestingly, 2023 had the third lowest overall lightning detections since
1998. The lightning-ignition efficiency was high due to extensive areas of dry, receptive ground fuels
coinciding with the specific timing and location of lightning events (Rao et al. 2023), a phenomenon that
is expected to increase as a function of the ongoing warming and drying (Hessilt et al. 2022). Although
they are responsible for a comparatively low proportion of the total area burned (7%), human-caused
ignitions were numerous early in the season, before the greening of vegetation and the prevalence of
lightning storms (Parisien et al. 2023). Many of these, notably in Alberta, burned for months and caused
evacuations of communities. Yet, it is difficult to confidently assign a human cause to some fires due to
ongoing investigations and the eventual intermingling of individual fires with multiple ignition sources in
large wildfire complexes.