Examining Wildfire Spread Variables for Assessing Forest Burn Vulnerability

Abstract

The scale and danger of wildfires are a growing concern in Western Canada. The Northwest Fire Centre is one of six designated wildfire management districts in the Canadian Province of British Columbia. It covers 25 million hectares, or a quarter of the area of the province. The centre sees the greatest area burned from wildfire spread in the province, although it experiences the lowest number of active wildfires annually. This study examined two Sentinel-2 images capturing the ‘before’ and ‘after’ of a major wildfire that took place in the Lutz Creek area within the Northwest Fire Centre in 2018. Higher-risk wildfire spread areas were identified by combining Normalized Difference Vegetation Index, Normalized Difference Water Index and slope gradient variables. When slope was included, the Moderately High and High burn vulnerability categories increased to ~54% of the area analysed, compared to ~33% when it was not included. Together, all three variables provide the basis for a more accurate assessment of forest burn spread and vulnerability.