Identifying and analyzing spatial and temporal patterns of lightning-ignited wildfires in Western Canada from 1981 to 2018

Abstract

To assess wildfire risk linked to lightning-caused wildfires, the present study tests the spatial- and temporal-scale distribution variability of lightning fires in Western Canada between 1981 and 2018. We examined clustering, trends, distances between clusters, and the fire season. For this study, the nearest neighbours, K-function, Moran's I, Mann–Kendall, and the Getis-ord Gi* statistics were used. These statistics were visualized by a Space Time Cube model with a hexagon grid. Lightning-ignited wildfires cluster spatially up to 270 km with an observed overall nonsignificant decreasing trend for the number of fires. Overall, northeastern Alberta, central Saskatchewan, and southeastern British Columbia show clustering of lightning fires. In June, there is significant clustering in northwestern and eastern Alberta, while in July fires cluster in northeastern Alberta and in southeastern British Columbia. In August, fire clusters occurred only in southeastern and south-central British Columbia. These results highlight regions that are experiencing persistent lightning fire clustering activity. This provides a focal point to assess wildfire risk to communities and values at risk, while informing local and regional management agencies in preparedness, resource capacity management, and detection. Additionally, it provides a baseline for future research into biophysical modelling of wildfire initiations.