MODIS-based smoke detection shows that daily smoke cover dampens fire severity in initial burns but not reburns in complex terrain

Abstract

Background Wildfire smoke may dampen fire severity through effects on weather and the persistence of atmospheric inversions, but empirical work on the link between smoke and fire severity is scarce. Aims To assess the influence of daily smoke characteristics on wildfire severity in complex terrain. Methods A customised smoke detection algorithm based on MODIS imagery was integrated into statistical models of fire severity across 106 wildfires between 2002 and 2018 in the Klamath Mountains, USA. Key results Smoke characteristics improved predictions of fire severity in non-reburn areas but not in reburns. Maximum daily smoke cover interacted with elevation, showing a strong dampening effect of high smoke cover on fire severity at low elevations consistent with prior work and a weaker amplifying effect on fire severity at middle elevations with low smoke cover. Conclusions Feedbacks between smoke and atmospheric inversions dampen fire severity in valleys but may amplify fire severity at middle elevations above inversion layers. Implications The influence of smoke on fire severity may strengthen in the future as large fires and extreme fire weather become more common, yet may also weaken as reburns become more prevalent.