Forest Fires/Smoke

Although smoke particles are too small to be detected by radar, the fierce convection above a well established bush or grass fire carries ash and other debris aloft which can be observed by radar. Downwind fallout of charred particles with dimensions of a centimetre or so is not uncommon. The high temperatures of the plume produce refractivity discontinuities that may be sufficient to cause appreciable reflection and scattering of radar energy. Reflectivity values up to 30dBZ and heights of 15km have been observed so that detection to moderate ranges can be expected in some instances. Echoes are typically sharp edged near the seat of the fire and extended downwind gradually becoming diffuse. The character of the echo is similar to that from rain.
 
 
Two smoke plumes observed on the Milwaukee, Wi doppler radar.