In 500 years, the Sierra’s stores of snow have never ben this low. PHOTO: François B. Lanoë/Nature Climate Change

Yet another ironical evidence of climate change. One in the mountains of Sierra Nevada, which coincidentally mean ‘snowy’ range. A new study has found that the snowpack in the Sierra Nevadas is the lowest it’s been in the past 500 years. Definitely not good news for California which depends on this snowpack for water. A debilitating drought, fierce wildfires, and now a declining snowpack, things sure are not looking good for the city.

By using data from weather stations, tree rings, and temperature reconstructions, a group of scientists were able to reconstruct snowpack conditions on April 1 of every year going back to the early 1500s. And this year’s low, they write in Nature Climate Change is “unprecedented” in the last five centuries.
For context, five hundred years ago, Europeans didn’t really know California existed. Spanish explorers didn’t even see the San Francisco Bay until 1769, less than 250 years ago. California didn’t become an American territory until the 1850s.

California depends on this snowpack for water during its dry summers. (Snowpack is made not just of one season’s snow, but of the accumulation of snow that gathers on a mountain, melts partially over the spring and summer, and grows again over the winter.) But it’s harder to reconstruct its historical levels than those of precipitation or drought. Studies like this one often depend on tree rings to reveal how weather played out in the years before people starting keeping track. But since trees grow in the summer and snow falls in the winter, the connection between the two variables can be a little shaky.
Most weather stations didn’t start tracking snowpack data until later in the 20th century, either. But in California, weather stations starting measuring snowpack early on, in the 1930s, around the same time the federal government decided to provide irrigation to the state’s Central Valley, now the heart of its agriculture industry.
“That alone is an indication of how important this snowpack is to California,” says Valerie Trouet, an associate professor at University of Arizona’s Laboratory of Tree-Ring Research and an author of the study.

Read more on how tree rings are climate change data hubs here.