Smoke: Stability

Atmospheric stability is the degree to which the atmosphere resists turbulence and vertical motion. This affects how smoke is dispersed. Consider the air heated over a prescribed burn. The more unstable the atmosphere, the more readily the lighter, heated air will rise by convection. Unstable air favors good smoke dispersal while stable air may cause smoke to hang close to the ground. Indicators of a stable atmosphere are steady winds, clouds in layers and poor visibility due to haze and smoke near the ground. Unstable conditions are indicated by dust devils, gusty winds, clouds with vertical growth and good visibility.