Flares are used for the safe, clean, and economical disposal of waste gases, whether in upstream oil production (solution gas flares), refineries, gas plants, or other chemical processing facilities. Elevated flares are exposed to a range of weather patterns; perhaps the most important being the crosswind. The CETC Flare Test Facility (FTF) was constructed to address the question of performance of solution gas flares, in response to limited field trials that indicated the possibility of very low combustion efficiencies under certain conditions. The FTF produces crosswind speeds up to 45 km/h with very low turbulence intensity, as designed. Model solution gases are produced from natural gas, propane, inert diluents (carbon dioxide and nitrogen), and volatile liquids. Atmospheric wind is a turbulent shear flow with an intensity of around 70%. To more closely replicate the turbulence properties of atmospheric wind, a range of turbulence intensities and integral length scales were imposed in the FTF by using grids. The flare flame efficiency is measured by the conversion of carbon in the solution gas to carbon dioxide. Efficiency is lowest for pure natural gas, and increases with the amount of propane. Conversion efficiency decreases significantly with the increase of turbulence intensity of the crosswind, which has implications for existing and novel strategies to improve flare performance. The primary product of incomplete combustion is methane, a significant greenhouse gas. The combined effect of inert diluents and turbulence intensity on flame stability shows that turbulence amplifies the destabilizing effect of fuel dilution.