Hazard index calculation for May 31, 1984 microburst at Erie, Colorado

The two x-band Doppler radars, operated by the NOAA Wave Propagation Laboratory, were used to collect high resolution data within a small, benign-looking microburst during the PHOENIX II boundary layer experiment. The lowest 2.5 km of the microburst was observed throughout its development and dissipation over a 15 minute period. These observations presented an excellent opportunity to compute a quantitative threat to a hypothetical aircraft whose flight track would carry it through the microburst. This hazard index is based on the kinetic energy loss to the aircraft that would be produced by the microburst; it is a function of the vertical air motion, horizontal spatial derivatives of the wind field, and the asssumed aircraft air speed and direction. Indices were computed and plotted for all eight volume scans and peak values were observed to be sufficiently high to present a significant hazard to an aircraft even though the virga-produced microburst was visually unimpressive.