Forecasters said a final round of rain, snow and high winds were targeting the Pacific Northwest and Northern California regions on Friday.

"The average atmospheric river carries an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi," NOAA states.

A major storm with heavy snow and record rain that's moving through Northern California has toppled trees, closed roads and prompted evacuations in some areas after knocking out power to hundreds of thousands of people in Washington and Oregon.