Over a month’s worth of rain, hurricane-force wind gusts and feet of mountain snow are coming to parts of the Pacific Northwest and Northern California.

With millions of people preparing to travel for the Thanksgiving holiday, two strong storm systems, including a bomb cyclone on the West Coast, are expected to bring high winds, heavy rain and snowfall to a large swath of the United States this week.

Bomb cyclone is a term used by weather enthusiasts to describe a process that meteorologists usually call bombogenesis. It's the rapid intensification of a cyclone in a short period of time, and it can happen during powerful storms such as the one no rthern California and the Pacific Northwest are preparing for this week.