California's biggest flood-warning winters were La Niña years

Every flood, flash flood and river flood warning the National Weather Service issued for California, November–March, colored by that winter's ENSO phase. The two strong El Niño winters, 2009-10 and 2015-16, were ordinary.

El Niño winterLa Niña winterNeutral
Data: every NWS flood, flash flood and river flood warning (VTEC) via the Iowa Environmental Mesonet archive; ENSO phase from NOAA CPC RONI.DisasterAWARE
Show the data as a table
Winter (Nov–Mar)NWS flood warningsFlash floodAreal floodRiver floodFlood advisoriesENSO phase (RONI)
2007-086358050La Niña
2008-0939381063La Niña
2009-10454104101strong El Niño
2010-117338926136La Niña
2011-12600640La Niña
2012-134918141765La Niña
2013-1420182068neutral
2014-1581481122122weak–moderate El Niño
2015-166141317137strong El Niño
2016-1735514094121294La Niña
2017-1821162384La Niña
2018-19158704048200weak–moderate El Niño
2019-20504190138neutral
2020-2118171058La Niña
2021-221082086La Niña
2022-23238789565413La Niña
2023-2493521724346weak–moderate El Niño
2024-2593312240239La Niña
2025-26127882217364La Niña