Abstract. The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18m (width)×18m (height)×40m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103–1…