At least one person has died and hundreds of thousands are are without power Wednesday as a powerful bomb cyclone approached the Pacific Northwest and Northern California, causing high winds and heavy rain and snow.

A historically strong bomb cyclone killed at least two people and caused a mass power outage that could last for days after it slammed the Pacific Northwest and Canada’s British Columbia with destructive winds.

One person is reported killed as the largest atmospheric river system of the year sweeps across California, Oregon, and Washington, where up to 16 inches of rain could fall.