Nov 22, 2024
The first atmospheric river of the winter storm season created flooding across the North Bay between November 20 and 23. The atmospheric river was accompanied by a very rapidly intensifying cyclone that deepened by 66 millibars within 24 hours, easily meeting the criteria for bomb cyclogenesis. The greatest impacts were concentrated across the North Bay as the river stalled over the region. The North Bay valleys received nearly a foot of rain in three days and the mountains received as much as 2
Source: NOAA National Weather Service Storm Events Database (event 1220584). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Contra Costa County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.