A powerful "bomb cyclone" storm has battered the US State of Washington, killing at least one person, downing trees and power lines, and leaving nearly 710,000 residents without electricity.

Thousands of people across western Washington were left without power Tuesday night as a powerful "bomb cyclone" brought strong winds to the north-west US.

A major atmospheric river is set to impact Western states this week, bringing a range of severe weather threats, including intense flooding rain, damaging winds, treacherous seas, and heavy mountain snow.