Following the bomb cyclone, the region faces days of rain, flooding and snow at higher elevations, the National Weather Service said Wednesday. That's part of an atmospheric river that could bring over a foot of rain to some areas.

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.

Storm system is expected to weaken as it continues to chart a path over the Cascades and through to northern California and southwest Oregon by Friday