California’s Changing Snowpack

By Mollie Ogaz

As a native Californian, the Sierra Nevada mountain range has long been a subject of awe and appreciation for me. Its granitic peaks, formed over millions of years by volcanic intrusions, uplift, and glacial erosion, are a unifying feature in a state so large and diverse. Forming the eastern edge of California’s Central Valley, the range runs 400 miles from north to south, providing both regions of the state with millions of acres of National Parks and wilderness to enjoy.

California’s Mediterranean climate (wet winters and dry summers) makes the Sierra Nevada a popular year-round destination for a variety of recreational activities. Some of my favorite childhood memories include the Sierras: camping and hiking in the summer and skiing in the winter. To this day, it never fails to amaze me how I can drive two hours and feel as if I am on a completely different planet, surrounded by geologic features so beautiful they are hard to put into words.

Breathtaking views and recreational opportunities, however, are far from the only benefits provided by the Sierra Nevada. The range is a pivotal piece of California’s water system, acting as a natural reservoir in the form of snowpack.  Accumulated during late-fall and winter storms, the snow slowly melts throughout the spring and summer, providing the State with a reliable source of water during the dry months.

As California struggles into a fourth year of drought, however, it is clear that the weather does not always go according to plan. Record-low snowpack levels have left the Golden State with a serious surface water shortage, resulting in hundreds of thousands of acres of farmland left fallow and groundwater pumping greatly surpassing levels that are sustainable. Personally, I experienced a few of the most frustrating ski seasons I can remember, waiting for storms that never came and sometimes having to rely on man-made snow to get my fix.

While drought is an inevitable feature of California’s climate, climate scientists at Stanford have found that climate change is “very likely” the cause of this one and that Californians should expect them more often in the future. According to their report, the atmospheric conditions that are the cause of the current drought are statistically more likely to occur as our world warms. It must be noted here that the above-mentioned report was very recently published (September 2014) and not all scientists are in agreement.

One change that is largely accepted by climate scientists, on the other hand, concerns how precipitation falls in California. Increasingly, more of the State’s annual precipitation will fall as rain, not snow. This shift presents a challenge to California because its expanding population, multi-billion dollar agricultural industry, and the environment itself all depend on the water stored in the snow to survive.

Losing that natural storage means water managers will need to be able to capture and store the rain when it falls in the winter for use in the summer, which is not as easy as it may seem. Reservoirs are intended to capture and store water, but they are also vital tools to battle flooding; requiring releases to make room for upcoming storms. With current infrastructure, most of the water released will flow out to the ocean, and therefore not be stored for later use, as it would be if in the form of snow.

It is clear that California faces a lot of challenges in the coming decades as its climate changes. For the iconic Sierra Nevada mountain range, this means a diminishing snowpack, with estimates of a 50% to 75% loss by 2100. As a skier, this is a disappointing reality, however the mountains I love will still be there to enjoy, just maybe not like I remember them. One thing is for sure, I am going to get as much skiing in as I can while the getting is still good.

References:

Hill, Mary. (2006). Geology of the Sierra Nevada (Revised ed.). Berkeley and Los Angeles, CA: University of California Press.

Howitt, R., Medellín-Azuara, J., MacEwan, D., Lund, J. Summer, D. (2014). Economic Analysis of the 2014 Drought for California Agriculture. California Department of Food and Agriculture and UC Davis Center for Watershed Sciences. Retrieved from: https://watershed.ucdavis.edu/files/biblio/DroughtReport_23July2014_0.pdf.   

Scripps Institute of Oceanography, UC San Diego. (2013). Scripps Researchers Assess the Future of Climate in California. Retrieved from: https://scripps.ucsd.edu/news/8155.

Swain, D.L., Tsiang, M., Haugen, M., Singh, D., Charland, A., Rajaratnam, B., and Diffenbaugh, N.S. (2014). The Extraordinary California Drought of 2013/2014: Character, Context, and the Role of Climate Change. In the Special Supplement to the Bulletin of the American Meteorological Society, 95 (pg. 3). Retrieved from: http://www2.ametsoc.org/ams/assets/File/publications/BAMS_EEE_2013_Full_Report.pdf

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