What Is a 'Bomb Cyclone'? Here's Why It's So Brutal

There are two culprits behind it all, according to the National Weather Service.

So, what do bomb cyclone and atmospheric river mean?

But bomb cyclones happen when thepressure suddenly and starkly dropsin the low-pressure-mass section.

That makes the pressure difference between both masses much more pronounced, which intensifies winds correlated with the storm.

Meanwhile, Earth’s rotation pushes these high-intensity winds across the globe – like those touching down in California.

What’s an atmospheric river?

Atmospheric riversare essentially narrow currents in the air that carry lots of water vapor across the world.

Highway 101 has turned into a moving river this afternoon.

The bomb cyclone more or less is “dragging” the atmospheric river in.

An atmospheric river approaches the western U.S.

But then it continued through the weekend, fell into Monday and has persisted on Tuesday.

“In addition to being highly moisture-laden, this rapidly intensifying system is also packing some thunderstorms.”

The bomb cyclone on Wednesday, Jan. 4, moving toward the coast of California.