A Hydrologic Reanalysis of the La Porte Anomaly

Abstract

The 1929?64 precipitation record at La Porte was analyzed through the use of a budgetary hydrologic model. Pre- and postanomaly data allowed accurate estimation of stream discharge for the La Forte region, but use of the anomaly period data caused consistent significant overestimation of discharge. If both the La Forte data and the stream discharge data are accurate, then La Porte can only be a small-scale phenomenon, affecting a small portion of the basin. The post-1960 disappearance of the anomaly could be explained by the movement of a local anomaly, dissipation of the anomaly mechanism by a reduction of atmospheric particulates, or elimination of gage and/or observer error. Of the three, gage and/or observer error appears most likely to be the cause of the anomaly.