Graphical method for determination of area-elevation weighting of snow course data

The paper discusses the forecast schemes used by the California Cooperative Snow Survey to forecast runoff during the April-July snow melt season, the problems encountered in the use of such schemes, and the basic considerations in the evaluation of a snowpack. The basin selected for study (Yuba Basin ) and the methods of evaluating the snowpack are described, snow survey data from the evaluating the snowpack are described, snow survey data from the basin are compared graphically, and a revised forecast scheme is presented. The results indicate that the evaluation of the snowpack on the basis of only a few selected courses may lead to unrealistic results. Graphs and explanations are shown to adjust the original forecast to include 5 independent variables. (1) Snow pack index adjusted for area-elevation, (2) varying precipitation and soil priming factor, (3) runoff occurring prior date of forecast, (4) antecedent conditions, (5) forecast period precipitation estimate.