The idea of a megadrought may sound alarming, but it's nothing new to the West. So, how does this drought compare to those of the past?
"If you're looking at single year droughts, it ranks pretty high over the last 500 years; it's about the third worst drought over the last 500," says Professor Lynn Ingram, a paleoclimatologist at UC Berkeley and the author of the "West Without Water."
However, there have been times when California has been dry for decades to even more than century if you look back 5,000 years.
"If you picture what we have this year extending a century long, that's what happened during the medieval period," Ingram says.
On average, California has been getting drier, but the 20th century has been relatively wetter compared to the last 2,000 years.
"It sort of gave people a false sense of what to expect in terms of precipitation," Ingram says. "Our population grew, we developed a huge agricultural industry, built reservoirs on almost every river" — essentially building a water system dependent on a level of precipitation the West may not always have.
"The region has extremely variable climate," Ingram says. "So, for the future, I think we really have to prepare for, perhaps, returning to a drier period."