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After prolonged rainfall or snow accumulation, enormous amounts of water can temporarily increase the load pressing on Earth's crust.
Modern GPS instruments are sensitive enough to detect tiny vertical movements of the land associated with changes in stored water.
When that water later evaporates, drains away, or melts and leaves the region, the surface can rebound.
Weather doesn't only change what happens above the ground—it can contribute to measurable movement of the ground itself.
© U.S. Geological Survey