Technical Abstract: Wind erosion is a serious problem in many parts of the world. Since the dust bowl days of the “Dirty Thirties,” numerous studies to understand the mechanics of the wind erosion process, identify major factors influencing wind erosion, and develop wind erosion control methods led to the development of a wind erosion equation (WEQ). This tool has been used with its many improvements for conservation planning. However, in spite of many improvements the limitations inherent in an empirical model remained, and a more process-based technology was developed. The Wind Erosion Prediction System (WEPS) was developed to improve wind erosion prediction technology for sustaining agriculture, protecting the environment, and conserving the natural resources against the ravages of wind erosion. This emerging process-based technology includes the capability to simulate weather, the field soil and crop conditions, and wind erosion on a daily basis. It provides new capabilities for assessing plant damage, calculating suspension loss, and estimating pm-10 emissions from the field. The predicted average annual soil loss from daily time-steps (WEPS) produces a different estimation of soil loss than the product of average annual values of factors affecting wind erosion (WEQ), as expected. Some of these differences will be illustrated and explained.