Heavy rain can overwhelm drains and raise San Francisquito Creek quickly. Strong winds can bring down trees and interrupt power. Repeated storms can saturate soil and leave trees unstable.
High Bay levels can slow drainage near the shoreline. Flooding may worsen when heavy rain, high creek flows and high tides overlap.
Areas to watch include San Francisquito Creek, Atherton Channel, Belle Haven, the Bayfront, low streets, underpasses and places with recurring ponding. Flooding can occur elsewhere.
El Niño is a seasonal climate pattern, not a forecast for a particular storm. Local effects depend on each storm’s strength, path and timing.