When a disturbance becomes organized around a low-pressure zone where winds are blowing at between 37 and 62 km/h, it is called a tropical depression. The depression develops into a tropical storm: the low pressure deepens, while winds rise to between 63 and 117 km/h. A tropical storm becomes a cyclone when wind speeds are above 118 km/h. In the eye that forms at the center of the cloud mass, the pressure drops to below 980 hPa. Deprived of its main source of energy, warm water, the cyclone weakens very quickly. The dissipation stage starts just a few hours after it travels inland.