Why is Sierra Nevada’s Warming Weather Alarming?

Last March, California officials announced that El Niño brought a greater snowpack in the Sierra Nevada mountain range than there has been in years. Despite this years snowpack, there are plenty of worrying signs in the mountain range, which, according to the state Department of Water Resources, is a crucial natural water reservoir. Natural systems and humans depend on the accumulation of snow as a vital source of water in the Northern Hemisphere. After the snow melts, it flows into rivers and reservoirs, proving about 30 percent of water to Californians in warmer months.

By capturing water in solid form in cold months and releasing it over time, snow serves as a backup reservoir, and any changes can affect how much water is available for people, industry and agriculture.

The snowpack is measured by inserting special metal tubes in the snow and later calculating how much water would result if the snow is melted. For example, 30 inches of snow on March 30 could be equivalent to about 12 inches of water. Usually, dry and powdery snow holds about 10 to 12 percent moisture by volume, and later accumulation and compression can increase the moisture content to about 40 percent.

Monitoring stations that record moisture conditions of the snowpack throughout the mountain range are already showing the effects of warmer temperatures. Historically reliable snow zones, where snow accumulates until March or early April and then melts, now behave as lower elevation zones, where the snow goes through a cycle of accumulation and melting at a faster rate. As temperatures warm, the altitude at which water is now stored becomes higher in elevation. This change in elevation means that less terrain is covered in snow.


Because warmer air can hold more moisture, researchers are expecting an increase of liquid precipitation rather than solid form in some areas, which means less snowpack storage and faster uncaptured runoff.

Despite a more favorable and wet El Niño across the northern half of the state, El Niño did not bring any major storms in Southern California, and with California’s traditional rainy season quickly fading into a hot, dry summer, the snowfall decline could present important complications to the hydrology of an area already expecting “dry winters” from La Niña.

With the uncertainty of the weather and the exacerbated effects of global warming, California needs to invest in a more sustainable infrastructure through water saving technologies that will lead the nation’s transformation toward a more drought resilient future.