More than 500,000 energy customers across the West Coast were without power early Wednesday and one person was killed by a falling tree as severe weather caused by back-to-back powerful storm systems began battering the Pacific Northwest.

A “once in a decade” bomb cyclone is sweeping through the northwest United States and parts of Canada early Wednesday –– leaving at least one person dead and hundreds of thousands without power across Washington state,

A bomb cyclone and an atmospheric river will continue lashing the Pacific Northwest with severe weather conditions, the National Weather Service said.