By analyzing ground positioning data collected by GPS stations across the West, researchers with Scripps Institution of Oceanography at UC San Diego estimate that, over the last two years, the intense heat and lack of rain -- plus the drinking needs or major cities and the water-sucking irrigation systems of area farms -- has sapped some 63 trillion gallons of water from the earth.
As ground water levels shrink, the earth uncoils like a spring and the ground rises. Water in the ground acts like an anchor, weighing down the earth's crust. But that anchoring effect is diminished as water tables slip lower and lower.
According to Scripps researchers Adrian Borsa, Duncan Agnew, and Dan Cayan the result is taller mountains and heightened plains. California's mountains have risen more than half an inch, while the rest of the American West has witnessed 0.15 inches of uplift.
The work of the Scripps geologists is detailed in the latest edition of the journal Science.
"The thing that is exceptional about this drought is that it really covers the entire region [of the Western U.S.]," the study's lead author Adrian Borsa told the Los Angeles Times. "I can't tell you whether this is as big as earlier droughts, but I would say within the last 10 years, this is definitely an unprecedented change with this drought."