Potentially deadly rogue waves are getting bigger off the US, a scientific study has found.

The research, published by Nature, studied the ocean off the west coast using 15 buoys between 1994 and 2016.

"Rogue wave occurrence displays a mostly decreasing trend, but the relative height – or severity – of the waves is increasing," the study said.

"We also identify seasonal intensification in rogue waves, with increased...occurrence,