Mar 1, 2018
An upper level system with a strong cold front moved through the Bay Area at the turn of the month with precipitation beginning late the evening of the 28th. This system brought widespread rainfall causing localized roadway flooding, strong winds, lightning, and small hail. Gusts in the mountains reached 60 mph and hail was seen up to 1/2 an inch. The bulk of the precipitation and subsequent impacts were seen in early March.
Source: NOAA National Weather Service Storm Events Database (event 737493). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in San Mateo County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.