A computer-based system to provide early warning in Western Canada, where the beef industry is particularly sensitive to drought, has been in operation since 1982. Nicknamed FoDEWS, for Forage Drought Early Warning System, the system uses a combination of current year#x2019;s weather data and historical weather data for late winter or early spring to project likely moisture reserves by late spring. The earliest predictions are made while the land is still snow-covered.By analyzing current weather records from drought-prone areas, more objective decisions can be made about who drought victims are, who the likely victims will be in future and where the need for assistance will arise. If needed, assistance can be given to beef producers more quickly and equitably. Also, the information will help producers find alternate sources of fodder earlier.The main component of FoDEWS is a computer model that calculates soil moisture from daily weather records. The model budgets rainwater, snowmelt and potential evapotranspiration over several soil layers on a daily basis. A sub-model for snow is a critical component for early warning.The model projects likely soil moisture conditions in late spring, using a process known as OVERWRITING. This process creates a full-year data file by combining the most recent weather observations with selected records from previous years. As current weather records become available, they replace corresponding dates of historical data.FoDEWS can assist in grazing land management by providing lead time to producers. Alternative practices to overgrazing can be implemented sooner. Such practices include trucking in hay or culling herds.FoDEWS is inexpensive to operate. It requires few human resources and the input weather data has already been collected for other purposes. The early warning reports, however, must be regarded as reconnaissance information because of the limited number of fast reporting weather stations in the region. Similarly, the projections to late spring should also be taken as interpretive outlooks, rather than as explicit predictions.
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