Methods of predicting snowmelt runoff are subject to many uncertainties. In part discrepancies arise in utilizing point snowfall measurements rather than direct measurement of the quantity of snow available within the snowpack. Determination of either the actual snow water-equivalent within a drainage basin or the potential snowmelt by means of index values (gauged at representative sites within the basin) presents many difficulties primarily because snow is very easily displaced by wind. Consequently, the snow accumulates on the ground in a highly heterogeneous manner and it becomes difficult to obtain representative measurements. The estimation of snowmelt runoff from a given drainage basin may be viewed along a continuum: at one extreme is the use of point snowfall as index of potential runoff while at the other end is a very intense monitoring of the basin snowpack water-equivalent (Figure 1.1). Clearly, both extremes are unacceptable, the former because of crudeness and the latter due to financial constraints. What is required is the best approximation of the absolute water-equivalent within the basin. Much current research has focused on developing sophisticated remote-sensing techniques of estimating areal values of water-equivalent but it is apparent that many problems still exist with these approaches (Ferguson and Pollock, 1971)...