This snow aquifer covers more than 27,000 square miles (70,000 square kilometers) — an area bigger than West Virginia — researchers report today (Dec. 22) in the journal Nature Geoscience. "We thought we had an understanding of how things work in Greenland, but here is this entire storage system of water we didn't realize was there," said Richard Forster, lead study author and a glaciologist at the University of Utah. Image caption The researchers drilled in areas with large accumulations of snow on the surface 
 
 They believe that it holds roughly 140 billion tonnes of water, which is the equivalent to 0.4mm of sea level rise per year - about half of what Greenland contributes to the sea every year. Every year, Greenland adds 0.03 inches (0.7 mm) of water to global sea level rise from melting snow and ice, Forster said. In the spring of 2011, researchers drilled deep into this slushy layer and to their surprise, found liquid water flowing back to the surface even though air temperatures were -15 degrees C. 
 
 As this was well before the onset of the summer melt, the team concluded the water had persisted in a liquid state through the Greenland winter. [Watch: Discover Greenland's Hidden Aquifer] 
 
 The water was stored in hard, compacted snow called firn — the remains of the previous year's snowfall.
– As far as discoveries go, this one is literally huge: An aquifer holding more than 100 billion tons of water that covers an area larger than West Virginia has been discovered beneath Greenland's snow-covered ice sheet. And it caught the researchers who stumbled on it in 2011 off-guard, with lead study author Richard Forster telling LiveScience, "We thought we had an understanding of how things work in Greenland, but here is this entire storage system of water we didn't realize was there." As for the "where," the aquifer was identified in the southeast part of the country, ranging from 15 to 160 feet beneath the surface, whose snow acts as an insulator, keeping the water liquid year-round. Forster gives this great description of how the water is stored, per the BBC: "in the air space between the ice particles, like the juice in a snow cone." But the find has raised plenty of questions, like: How old is the water? Does it stay where it is, or trickle to the sea ... or rush toward the sea in a flood? In a separate study, the team determined that if released, the aquifer's water could push global sea levels up 0.015 inches. And in terms of sea level rise, LiveScience explains that scientists have long assumed that most of the water produced in the country's annual surface melt streams toward the ocean, or eventually refroze; the aquifer is essentially a "new hiding place," one that researchers can study to get a better grasp on the annual melt. Says Forster, "We need to understand it more completely if we are to predict sea level rise."