A weather circulation pattern called “The Pineapple Express” is shown on this satellite photo from NOAA, from 2006.

This circulation brings moisture from the South Pacific, near Hawaii (Pineapple), at a very fast pace (Express) towards the North-Western coast of the United States and British Columbia. This weather pattern can sometimes remain quasi-stationnay for as long as a week or more, continuously pumping moisture, rain and snow, to the same geographical location. 

In the last week, The Pineapple Express has been responsible for the recent Washington state floods, which have broken long-standing records.

Watch this YouTube video from Associated Press.