Predicting hurricane frequency and intensity
As discussed, modern methods of weather forecasting involving satellites, radar, etc. allow accurate tracking of the development and paths of hurricanes. In addition, computer models have been developed that enable the prediction of storm surge levels along the coast, given data on wind velocity, wind distribution, and storm center velocity. Computer models have also been developed to predict the paths the storms will take and have met with moderate success. Accurate forecasting of storm tracks is more problematical because of the numerous variables involved and the erratic paths hurricanes sometimes take.
Drought and famine
In contrast to the exceptional weather conditions we have discussed so far, which tend to bring high quantities of rainfall, a drought is a period of time of abnormal dryness in a region. Droughts are slow onset hazards that may lead to secondary effects like famine In Australia, droughts are caused when upper level air flow creates a long lasting high pressure ridge over the central region. The high pressure causes cyclonic flow bringing dry air down to the surface. As this air sinks in the high pressure areas it warms and the relative humidity decreases further. Thus the air is so undersaturated with water that it sucks up even more water from the surface. Such persistent high pressure zones block the flow of warm moist air preventing storms that would normally bring rain.
