Sierra Nevada Mountain Range registered 24 mm rise during drought years

Sierra Nevada Mountain Range registered 24 mm rise during drought years

Sierra Nevada mountain range in California witnessed a rise by 24 millimeters (one inch approximately) during the drought years in the state. A research conducted recently has noticed that the rise was witnessed between October 2011 and October 2015. The study conducted by NASA’s Jet Propulsion Laboratory scientists added that the natural phenomenon occurred due to loss of water from the Sierra Nevada mountain range. The study team evaluated data from 1,300 sensors placed at different locations in the mountain range in California, Oregon and Washington.

Sierra Nevada mountain range has been growing due to gradual shift of the tectonic plates. Groundwater pumping in the central valley region had also led to sinking of some parts. As drought worsened the conditions for farming community in many regions across California, farmers were forced to pump more groundwater.

NASA scientist and study author Donald Argus informed that heavy precipitation weighs down on mountains and as there was less weight on the mountains, there was a small shift. Argus added, “It’s like a bathroom scale. When you took the water off, it rose.”

However, during the last two winter seasons, there has been good amount of rain in Sierra Nevada. This has led to nearly half inch decline in the height, the research team noted. The seasonal fluctuation in the height have been factored in by the research team.

Argus said the study provides some fresh insights into how the mountains behave. In particular, the research shows that the Sierra acts more like a sponge than previously believed; during the spring snowmelt season, a lot of water stays in the mountains.

The research paper titled “Sustained water loss in California's mountain ranges during the severe drought from 2012 through 2015 inferred from GPS” has shared the data between year 2006 and 2017. The sensors have been installed under National Science Foundation's Plate Boundary Observatory project.

“One of the major unknowns in mountain hydrology is what happens below the soil. How much snowmelt percolates through fractured rock straight downward into the core of the mountain?” said Jay Famiglietti, jet propulsion lab scientist who participated in the research. “This is one of the key topics that we addressed in our study.”

The researchers had to account for other reasons why the surface of the Earth rises and falls, including tectonic uplift or the extensive pumping of groundwater in the Central Valley, which runs along the Sierra.