What is actually an atmospherical stream?

.FOR CALIFORNIANS it felt like recognition. Last year a ceremony of tornados, fed by atmospherical rivers, eliminated at least 21 folks and created virtually $5bn-worth of harm all over the state. On February 4th this year the exact same kind of hurricane again ravaged.

Hurricane-strength winds buffeted the core coast near Big Sur. In Los Angeles celebs were saturated as they reached the Grammy awards’ ceremony. Mansion houses in the Hollywood Hills were actually covered in mud.

A minimum of three people have actually perished. What are climatic rivers, and are they a danger past California?