An empirical model of a downburst

A “downburst” was defined as a strong downdraft which induces an outburst of damaging winds on or near the ground. Such events normally occur during thunderstorms. It has been well documented that downbursts cause frequent failures of high voltage electricity transmission towers in Australia, and several other countries. The present paper describes a model of the horizontal wind speed and direction in a travelling downburst, generated by the vector summation of the “environmental” wind speed, or translation speed, and the radial wind generated by an impinging jet. Good agreement is achieved between the model and recorded data from a high intensity downburst that occurred at Andrews Air Force Base in 1983.