The massive winter storm that began to strike Northern California and Nevada over the weekend has caused flooding and mudslides, and prompted evacuations across the region, with a second storm set to hit Monday evening. With California’s ongoing drought entering its sixth year, the massive rainfall is unusual and welcome, by some. The weather pattern driving the rain is a meteorological phenomenon known as a “pineapple express,” not to be confused with the Seth Rogen and Dave Franco comedy film of the same name.