From the edge of the storm toward its center, the atmospheric pressure drops sharply and the wind velocity rises. The strength of a hurricane is rated from 1 to 5. Hurricanes generally move in a path resembling the curve of a parabola. In the northern hemisphere the storms usually travel first in a northwesterly direction and in the higher latitudes turn toward the northeast. In the southern hemisphere the usual path of the hurricane is initially to the southwest and subsequently to the southeast.
Hurricanes travel at varying rates.
Those areas in which the hurricane winds blow in the same direction as the general movement of the storm are subjected to the maximum destructive violence of the hurricane. Since 1943 U.S. military aircraft have been flying into hurricanes to measure wind velocities and directions, the location and size of the eye, the pressures within the storms, and their thermal structure. A coordinated system of tracking hurricanes was developed in the mid-1950s, and periodic improvements have been made over the years. Improved systems of prediction and communication have been able to help minimize loss of life in hurricanes, but property damage is still heavy, especially in coastal regions.