What might El Niño mean for winter weather in the US and Canada?

California could well find itself in the firing line with forecasts suggesting a wet winter is likely.

Governor Gavin Newsom has already declared a state of emergency, external ahead of anticipated floods and mudslides.

Areas scarred by recent wildfires are particularly susceptible, with the effects of climate change exacerbating the risks.

Many past El Niños have been wet here, with winter 2023-2024 bringing relief from drought. However this is not always the case. In the strong El Niño of 2015-2016, California actually had below-average rainfall.

Coastal erosion and large waves could be worsened by a rise in the overall sea level driven by so-called Kelvin waves.

This is where ocean water which sloshes eastwards across the Pacific due to El Niño reaches the west coast of the Americas, where it can travel no further.

It causes a large-scale wave which then spreads along the coast over a period of weeks and months, raising sea levels by 15cm (6in) or more.