tidal

The contest is staged in a former slate quarry that was flooded by a tidal wave in 1881.

The recent surge in reactionary politics has been accompanied by a tidal wave of “trad” propaganda, which argues that feminism is bad for women and they would be happier in circumvented roles at home.

The process of salt collection in San Francisco Bay was industrialised in the 1800s but now the bay's salt ponds are part of a major restoration project, bringing back tidal marshes and wildlife.

"Big surf means greater risk from rip currents, and the swell also coincides with spring tides, which means more powerful tidal water movement at greater speed," Mr Cousens said.

Further south, there were tidal surges of up to 0.7m in San Francisco.