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Snow Sciences |

For 75 years, the Central Sierra Snow Lab has been studying the Sierra Nevada snowpack

Longtime (and now retired) director Randall Osterhuber of the CSSL measures the snowpack at the Donner Pass field site. Photo / Central Sierra Snow Lab

Perched atop Donner Pass, over 7,000 feet, is the Central Sierra Snow Lab, a field research station responsible for maintaining the West’s longest snowpack measurement.

Established in 1946 by the US Weather Bureau and the Army Corps of Engineers, snow specialists have since occupied the station collecting data on precipitation, snowfall, snow depth and temperature. the air.

“If you combine this with the snow measurements that were collected from the Southern Pacific Railroad, the record actually dates back to 1879,” says Dr. Robert Rhew, director of the CSSL station and professor at UC Berkeley, which manages installation since 1996..

On two hectares, the station houses seven buildings and instrumentation fields for collecting data on other aspects of snow physics and hydrology, meteorology and climatology, wind speed and from solar radiation to snow temperature and relative humidity.

“The sheer amount of precipitation might not give you the whole story. Just the amount of snow may not give you the whole story. You have to measure all of these things together, including things that we haven’t measured before, just to fully understand the complexities of climate change in this region, ”says Rhew. “It varies from year to year, but having a long-term history allows you to see changes over a long period of time. “

Understanding the Sierra Nevada snowpack, its water content (known as the water equivalent of snow), and the factors impacting its melting, such as rain on snow, is essential for managing snowfalls. California and Nevada water supply budgets, which are heavily dependent on snowmelt.

The CSSL houses numerous instruments for measuring all aspects of snow hydrology, meteorology and climatology. Photo / Central Sierra Snow Lab

The study of the California snowpack began at the turn of the 20th century with Dr. James E. Church, known to many as “the father of snow surveying”. Church, a professor at the University of Nevada at Reno, created the first weather observatory on the summit of Monte Rosa at 10,776 feet and, in his research, found that the depth of snow does not equal the amount of water in the powder. He then developed pioneering methods to measure snow depth and water content.

Today, the study of snow has become much more complex, although the snow scientists in the laboratory continue to crawl after every storm to collect snow cores for study, as they would have done at the era. The lab relies on tools such as snow cushions, antifreeze-filled bladders designed to automatically measure the weight of snow, as well as instruments from dozens of government agencies, non-profit organizations and universities collecting data on all weather events. They are also developing new methods of measuring the water equivalent of snow that could be used around the world, such as a gamma-ray sensor that captures data before the snow hits the ground.

Previous research projects in the lab have investigated how snow impurities like black soot and other pollutants change the color and reflectivity of snow, resulting in greater sun absorption and faster melt time.

“We hope to attract more and more of this research as people become interested in the intricacies of winter hydrology in the Sierras and want to do these experiments at a location where we have the most instruments of any snow lab.” over there, ”Rhew notes.

While the details of snow science may seem abstract to a layman, research conducted at the CSSL has direct implications for our understanding of water supply management and the impacts of climate change.

In 2019, with the retirement of the director and sole operator of the CSSL, Randall Osterhuber, after more than 20 years, followed by budget cuts and the pandemic, the future of the snow lab was uncertain. Fortunately, Rhew and the partner organizations that benefit from the station’s research did not allow the lab’s legacy to end.

“Now we have a new snow specialist at the field station who fixes everything, continuing the legacy of the measurements taking place there, re-establishing all those links with government agencies and also directing the snow lab into new ones. directions, ”says Rhew.

“A big part of the value of this facility is that it has a long-term data set. We need this perspective to be able to understand what is happening on our planet. “