A Pineapple Express forms when the jet stream dips south into the tropical Pacific near Hawaii, scooping up warm, moist air and carrying it northeast across the ocean. Named for Hawaii's famous fruit and the storm's origins near the islands, these powerful systems can dump the equivalent of 10 to 15 inches of rain over two to three days.

Three atmospheric rivers delivered big rain and snow totals to Northern California. Here's a look at how much fell.