Atmospheric Rivers
The storms are due to a series of what are known as atmospheric rivers, or bands of air carrying a lot of moisture that can cause heavy rains and snow on the West Coast. The National Weather Service said Wednesday that heavy rain and some snow are expected over parts of California through Friday evening, which will cause “localized areas of flash flooding, with urban areas, roads, small streams, and burn scars the most vulnerable.” Some 5 million people were under a flood watch.
