Sierra Nevada, California – Scientists found that the snowpack level in Sierra Nevada during 2015 was the lowest in more than 500 years.

“We were expecting that 2015 would be extreme, but not like this…. Our study really points to the extreme character of the 2014-15 winter. This is not just unprecedented over 80 years—it’s unprecedented over 500 years,” said Valerie Trouet, an associate professor of dendrochronology at the University of Arizona’s Laboratory of Tree-Ring Research, in the University’s press release.

Snowpacks are formed from layers of snow that accumulate in certain geographic regions and high altitudes where there are cold weather during long periods of time through the year. Snowpacks represent an important water resource that feed streams and rivers as they melt. According to the University of Arizona report, California gets 80% of its precipitation during the winter, and the snowpack serves as 30% of its water supply.

A Sierra Nevada lake surrounded by snow barren ridges, that are usually covered in snow this time of year, are seen during an aerial survey of the snowpack. (AP Photo/Rich Pedroncelli)

“This is probably the biggest water supply concern our state is facing. On a scale of 1 to 10, it’s 11,” said Mark Gold, associate vice chancellor for environment and sustainability at UCLA.

The research, published in the journal Nature Climate Change, is the latest of a series of studies that have analyzed and tried to raise awareness about the California’s four-year drought. It also joins a growing warning that climate change will ultimately reduce the snow blanketing in California’s mountains causing a concerning reduction of available water. The drought that began in California by 2012 has been labeled as the worst in over a millennium, and researchers predict that humanity can expect more “megadroughts” in the future.

According to UC Davis hydrology expert Helen Dahlke, the issue is that because of climate change, there will be more rain but much less snow. “That water will just be going into the ocean unless we can figure out a way to capture some of that water quickly,” said Dahlke.

The preservation of the snow in regions such as California is that, ”Snow is a natural storage system,” added Trouet. “In a summer-dry climate such as California, it’s important that you can store water and access it in the summer when there’s no precipitation.”

The Research

For the study, funded by the National Science Foundation, the US Geological Survey and the Swiss National Science Foundation, the team looked at previously published data of tree rings from blue oaks in California’s Central Valley. The rings’ width would determine the annual winter precipitation.

Trouet and colleagues also used previous work by Eugene R. Wahl of the National Oceanic and National Centers for Environmental Information, who had reconstructed temperatures from January to March in the area between 1500 and 1980. Finally, the experts used modern snowpack measurements, which have been conducted at Phillips Station since 1941.

Results showed that the amount of water contained in the snow on April 1, 2015, was only 5% of the average snow water since monitoring began, while the snowpack usually reached a height of 5 1/2 feet at that time of year.

Source: Nature Climate Change