Winters with little or no snow could become commonplace in the Sierra Nevada as soon as 25 years from now, according to an alarming new study.
2015, at the height of the last drought when Sierra snowpack measurements came in lower than they had since records were being kept, might turn out to be a very typical year in future decades. And while mountain areas across the Pacific coast will be impacted by a warming planet, the Sierra Nevada will likely be the first to lose the snow. This is what's spelled out in a new study led by researchers at Lawrence Berkeley National Laboratory, published in the journal Nature Reviews Earth and Environment.
"It’s always shocking when I see the numbers," says Berkeley hydroclimate researcher and California native Alan Rhoades, speaking to the Chronicle. "Snow has always been part of my life, since childhood."
The study suggests that low or no snowpack could persist for five-year stretches by the late 2040s, given current climate-change patterns. "Low" snowpack is defined as falling in the 30th percentile of the region's historical peak, and "no snow" is defined as the 10th percentile or lower, which would be like 2015. By the late 2050s, the study says, these relatively snowless winters could persist for ten years at a time — and all of this spells future disaster not only for the ski industry, but for California's water needs.
Much of Northern California's water supply comes from the Sierra snowpack, the melting of which typically provides water flow into rivers and streams well into the early summer. As the Chronicle notes, that flow has already been impacted by the current drought, which has decreased the runoff efficiency, i.e. how the melting snow reaches our water sources — mainly because it is being reabsorbed into drought-parched soil before it gets to those rivers. Runoff efficiency, according to state officials, averages around 60%, but this past spring it was down to 20%.
As an adaptation strategy for a future with less snowpack, some experts are calling for the construction of new reservoirs to capture and store more excess water in the winter. Others, like Ellen Hanak, director of the Water Policy Center at the Public Policy Institute of California, tell the Chronicle that we should be storing more water in underground aquifers — a practice called groundwater recharge.
"California is really well positioned to use aquifers in an active way by recharging them," Hanak tells the Chronicle.
Still, this is a grim update to an already scary forecast for Northern California's future, as we adapt to more extreme and longer fire seasons, and perhaps repeated droughts.
Little or no skiing by 2045 is depressing enough. But think about the fact that communities like Mendocino and Cambria are currently suffering from severe water shortages in what has otherwise been a fairly normal drought year. What happens when such shortages hit major metropolitan areas like the Bay Area, all because there's been little snow for several years?
Photo: Joey C