Using 50 years of stream-flow data from California's coastal mountains, together with the compositing of 925 mb geopotential heights from the NCEP/NCAR global reanalysis database, it is demonstrated that the varying impact of the rain shadow observed across the Santa Cruz Mountains during the single case study was also apparent when examining flooding events whose exceedance probabilities were less than 0.2, i.e., all flooding events whose discharges exceeded the magnitude of a 5-year flood. Specifically, flooding events on the eastern side of the Santa Cruz Mountains required low-level flow that was more westerly than during flooding events on the western portion of these mountains. The phase of the El Niņo-Southern Oscillation (ENSO) also impacted the probability of flooding on the eastern and western sides of this mountain range. The low-level flow was more meridional during the warm phase of ENSO (i.e., El Niņo) and more zonal during the cold phase (i.e., La Niņa). Hence, the eastern Santa Cruz Mountains were anomalously dry due to rain shadowing during El Niņo years and anomalously wet during La Niņa years, an ENSO relationship that is opposite relative to the other coastal sites in central and southern California.