Wind is essentially a random phenomenon. In the past, it was considered sufficient to use the mean wind speed that had been recorded at the nearest meteorological station. The corresponding wind pressure was applied statically. This was an erroneous practice since wind loading varies with time. In addition to steady wind, there are effects of gusts which may last for a few minutes. Gust causes increase in air pressure and may affect only part of the building. The increased local pressures may be more than balanced by a momentary reduction in the pressure elsewhere. Because of inertia of a building, short period gusts may not cause any appreciable increase in stress in the main components ...