An empirical model of a downburst

A "downburst" was defined as a strong downdraft which induces an outburst o f damaging winds on or near the ground. Such events normally occur during t hunderstorms. It has been well documented that downbursts cause frequent fa ilures of high voltage electricity transmission towers in Australia, and se veral other countries. The present paper describes a model of the horizonta l wind speed and direction in a travelling downburst, generated by the vect or summation of the "environmental" wind speed, or translation speed, and t he radial wind generated by an impinging jet. Good agreement is achieved be tween the model and recorded data from a high intensity downburst that occu rred at Andrews Air Force Base in 1983. (C) 2000 Elsevier Science Ltd. All rights reserved.