What is an atmospheric river? Meteorologist Dallas Raines explains

We're tracking an atmospheric river heading toward Southern California, but what is the system? Chief meteorologist Dallas Raines is breaking it down.

It all starts with warm, tropical water - such as the current conditions being created by El Niño.

That warm water is released into the atmosphere in the form of vapor. At times, that process can generate the same amount of water that's contained in the Amazon River.

That water then begins moving toward California through a process known as Integrated Vapor Transport (IVT).

If the system gets high enough, that's when we can get really heavy rain and snow. In California, that moisture can be lifted by coastal mountain ranges and the Sierra Nevada farther inland.

Atmospheric rivers are categorized similar to hurricanes, gauging how much rain they have the potential to bring.

Watch the video in the media player above for more.