US authorities warn of coastal flooding in California

The US National Weather Service (NWS) has warned of powerful waves crashing onto beaches and overtopping seawalls in California, as the state braces for a series of storms bringing heavy rainfall and rough seas.

Waves are expected to reach heights of around nine metres off the coasts of San Francisco and the Big Sur region, raising concerns over flooding in low-lying coastal areas.

Authorities said the high waves could flood nearby structures, urging the public to stay out of the water and keep away from piers, harbours and rocky areas.

The warnings come after waves generated by a tropical storm caused damage in Long Beach in recent weeks, destroying sections of the waterfront, flooding a residential neighbourhood and damaging homes that are now at risk of collapse.