Eleven trillion gallons of water are needed to end the three-year drought in California, NASA reported on Tuesday, after a research was made on the water resources with the use of the satellite data. Though California has experienced rainstorms recently, scientists warned that those were not enough to end the drought.

According to data presented by NASA scientists at the American Geophysical Union in San Francisco, 11 trillion gallons below normal seasonal levels are needed in water storage in the Sacramento and San Joaquin river basins. As reported by The Verge, those basins have decreased in volume by 4 trillion gallons of water per year, an amount that overtook the quantity used by the residents in California yearly.   

The latest NASA information showed exactly how severe the epic drought in California. According to Yahoo! News, the pioneer calculation of the quantity of groundwater, which is 11 trillion gallons, needed to end the drought was led by Jay Famiglietti of NASA's Jet Propulsion Laboratory in Pasadena, California and based on the observations from NASA's Gravity Recovery and Climate Experiment satellites.

"It takes years to get into a drought of this severity, and it will likely take many more big storms, and years, to crawl out of it," Famiglietti stated. "Spaceborne and airborne measurements of Earth's changing shape, surface height and gravity field now allow us to measure and analyze key features of droughts better than ever before, including determining precisely when they begin and end and what their magnitude is at any moment in time. That's an incredible advance and something that would be impossible using only ground-based observations."

Since 1949, scientists reported that the entire southwestern US is far drier than usual, with groundwater levels across the region in the lowest 2 to 10 percent.

Meanwhile, aside from the 11 gallons of water data, NBC News said another satellite data showed that California's Sierra Nevada range snowpack is only half the previous estimates this year.

"The 2014 snowpack was one of the three lowest on record and the worst since 1977, when California's population was half what it is now," Jet Propulsion Laboratory's Airborne Snow Observatory chief investigator Tom Painter said.

Although California has been struck by autumn storms pouring the desperately-needed rain, it was still not enough to end the region's drought, which was the worst seen for over 1,200 years, The Daily Mail reported. And what California really needs is about 11 trillion gallons of water to finally end the multiyear drought.