Observations on a 25 km Microwave study link operating at 10.5 GHz revealed that the attenuation caused by dust storms agrees very well with theoretical predictions. During an extremely dense storm, at the peak of which visibility dropped to less than 5 meters, the maximum attenuation observed was less than 7 dB. The computed value lies between 3.8 and 10.2 dB. The uncertainty is due to lack of information on the exact visibility during the storm. The effect of dust particles precipitation is found to reduce attenuation in an exponential manner. An analysis based on particles size distribution and their terminal velocity in air is developed to explain the observed exponential decay.