Does El niño affect snowpack in Utah

Nine snow gauging stations in Utah are analyzed to detennine the impact of El Nino on snowpack (snow water equivalent) across the state. The stations were chosen based primarily on the length of record. The effect of latitudinal variation as well as temporal variation on El Nino impact is considered. The importance of the stationary atmospheric wave pattern in the N. hemisphere during El Nino events is demonstrated. The Pacific North American (PNA) pattern provides a convenient and effective measure of the state of the atmospheric wave pattern that impacts Utah. A response table showing the impact of various combinations of El Nino and the PNA pattern shows that significant impacts on snowpack occur when both the El Nino and PNA indices are at extreme values. Correlation analysis reveals that N. Utah is negatively correlated with El Nino, while S. Utah is positively correlated with El niño, with the transition between these two extremes being nearly linear. A forecast based on the results is presented, which indicates that the next two years will be near-normal.