A closer look at the seasons with the most damage shows occurrences of high intensity-short duration precipitation events that overwhelmed California's flood control capabilities.  Examination of several of these events shows some important common characteristics as well as the differences between ENSO and non-ENSO years.

January and March 1995 Storms were both events of extremely high one day rainfall rates concentrated over a relatively small region (i.e., less than 100 miles wide).  Figure 1 and Figure 2 (Goodridge, 1997) show areas where there were large swaths where 100-year storms occurred, with embedded 500 and 1000-year events.  These events had over 100 stations which had their greatest one day rainfalls in the station's history.

New Years Storm 1997 was another relatively short-duration high intensity storm.  Figure 3 (Archer, 1997) shows the 24 hour rainfall across northern California with several regions exceeding 8 inches for the period.  Several more comparable days, with the addition of significant snowmelt in the Sierra Nevada led to widespread flooding in the Sacramento and San Joaquin Valleys.   Goodridge noted over 50 stations in the period from December 20, 1996 to January 3, 1997 that received their historical one day totals.  Interestingly, the seasonal rainfall totals for most of California were very close to their 30 year normals.

Winter 1982 - 1983 was during a very strong ENSO event with near record seasonal rainfalls over a large portion of California with 512 stations reporting their highest seasonal totals ever (see Figure 4).   There was generalized flooding over a wide area without the benefit of any single major high intensity event with about $854M in damage.  Additionally, on October 26, 1982 another $563M in agricultural damage was reported in central California when tropical moisture from former Hurricane Sergio spread over the state.