The influence of the El Nin??o-Southern Oscillation (ENSO) phenomenon on flooding in California coastal streams is investigated by analyzing the annual peak floods recorded at 38 gauging stations. The state of ENSO prior to and during flooding is characterized by the multivariate ENSO index (MEI), where MFI < -0.5 is defined as the La Nin??a phase and MEI > 0.5 as the El Nin??o phase. Flood magnitude in all 20 streams located south of 35??N has a significant positive correlation (r = 0.3 to 0.6), whereas in 3 of the 4 streams located north of 41??N flood magnitude has a significant negative correlation (r = -0.3 to -0.4), with MEI from -2.2 to + 3.2. Correlations with MEI are uniformly weak and insignificant, however, when the floods [...]
