Scientists who track subtle gravitational field changes in river basins have found they can tell which areas of the globe could be most likely to flood. Fox News reports on the study recently published on July 6 in the journal Nature Geoscience.

Flood Satellite

Studying water levels

In the study, researchers took measurements of how much water was in a river basis before the spring flooding season came. Then they looked at historical satellite data, using it to take measurements about the amount of water that saturated the ground ahead of the Missouri River flooding in 2011. They found that the statistical model they developed gave strong indicators that a major flood was about to happen five months before it did. Researchers said they may be able to predict a major flood up to 11 months out, although predictions that far ahead of time would be less reliable.

The 2011 Missouri River flood lasted months, soaking farmland, closing nuclear plants and shutting down highways. A month before the floods rolled in, the National Weather Service issued flood warnings.

NASA’s GRACE satellites

The data researchers used for the study came from the two GRACE satellites launched by NASA. Their orbits around Earth were affected slightly due to changes in the planet’s gravitational pull. Scientists say these small pulls indicate that the planet’s mass is changing slightly due to impacts from a buildup of water and / or snow. NASA originally launched the satellites to keep an eye on ice sheet melting.

At this point, researchers have only used their statistical method to examine past floods. In addition, they said only some types of floods can be predicted using their model. Flash flooding caused by sudden downpours, like what happens during monsoon season in India, could not be predicted.

Scientists also said it takes about three months for researchers to gather data from the two satellites, which means they can only predict floods two or three months ahead of time. That’s not much different than the amount of time current ground methods of measurements provide. However, NASA is looking at ways to speed up how fast its data is delivered, bringing it down to 15 days.