Atmospheric rivers are like rivers in the sky, which transport large amounts of water vapour from the equator northward. CBC meteorologist Johanna Wagstaffe said the weather system will be bringing a long episode of heavy rain to the South Coast. "The atmospheric river is hitting the South Coast through Friday and into the weekend, basically a plume of moisture, bringing all of that rain from the western Pacific and it will feel like we are at the end of a fire hose aimed right at the South Coast," explained Wagstaffe.