LOS ANGELES (KABC) -- Scientists believe the snow in the Sierra Nevada Mountains is at its lowest level in 500 years.
The mountain snow is a critical source of water for the entire state.
But according to research published Monday in the journal "Nature Climate Change," we have not seen snow levels this low since around the time of Columbus.
Scientists made the determination by studying some old trees, which grow larger rings in wetter years.
Snow in Sierra Nevadas at lowest level in 500 years