Opinion | California’s Drought Is Worse Than We Thought

Outside my lab near Donner Pass in California’s Sierra Nevada, there are new animal tracks in the snow after a winter of hibernation, birdsong wafts through the air, and the creek runs strong with spring water. the melting snow. Spring has come worryingly early in the Sierra Nevada.

Last week, I joined teams of other scientists to collect the most important measurements of Sierra Nevada snowpack at more than 265 sites across the state. This measure typically marks the transition from snow-accumulation season to melt season and contains the most snow of any measure throughout the year. However, the 2022 results confirmed what those of us monitoring the state’s drought had feared: California’s snowpack is now at 39 percent of its average, or 23 percent less than at the same point. last year. This signals a deepening of the drought, already the worst in the western United States in 1,200 years, and another potentially catastrophic fire season for much of the West.

Many people have a rather simplistic view of drought as a lack of rain and snow. That’s accurate, up to a point. What it doesn’t take into account is human activity and climate change that are now dramatically affecting available water and its management. As more frequent and larger wildfires and prolonged dry spells ravage the earth, our most important tools for managing water become less and less precise. At the same time, our reliance on these models to try to make the most of what little water we have is becoming increasingly problematic.

Droughts can last for several years or even more than a decade, with varying degrees of severity. During these types of prolonged droughts, the soil can become so dry that it absorbs all the new water, reducing runoff into streams and reservoirs. The ground can also become so dry that the surface becomes hard and repels water, which can cause rainwater to run off quickly and cause flooding. This means that we can no longer rely on relatively short periods of rain or snow to fully alleviate drought conditions as we did with previous droughts.

It would take many storms with near-record amounts of rain or snow in a single year to make a significant dent in drought conditions. October was the second-snowiest month and December the snowiest month on record in the snow lab since 1970, thanks to two atmospheric rivers that hit California. But exceptionally dry periods in November and January through March have left us with another year of below-average snowpack, rain and runoff conditions.

This type of feast-or-famine winter with major storms and long, severe dry spells is expected to increase as climate change continues. As a result, we will need several years of above-average rain and snow to make up the difference rather than large back-to-back events in a single year.

Even with years of normal or above-average rainfall, changes in the Earth’s surface present another complication. Massive wildfires, like the ones we’ve seen in the Sierra Nevada and Rocky Mountains in recent years, cause distinct changes in the way snow melts and water, including rain, runs off the landscape. Loss of forest canopy from fire can lead to higher wind speeds and temperatures, which increases evaporation and reduces the amount of snowwater reaching reservoirs.

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Similar to prolonged drought, fire also alters soil properties and can create flash floods during intense periods of rain. These changes in the landscape, feast-or-famine precipitation patterns, and increased demand on the water supply are making water management in the West a precarious and difficult task.

One of the most important tools for managing water during periods of drought are the models developed by various state and federal agencies, such as the National Weather Service’s Office of Hydrological Development, the Army Corps of Engineers, and the US Department of Water Resources. California. However, these models suffer from the same simplistic view of drought and water, and are in dire need of an update.

Land surfaces, snow melt patterns, and climate have all changed since many of these models were developed, meaning they are missing crucial pieces of today’s water puzzle. What has prevented model updates for decades is declining funding for science and engineering.

Models may not be able to reliably tell water managers how much rain and snow will run off the land into reservoirs, which can mean severe shortages in the worst case. Given declining reservoir levels and scant snow cover in recent years, discrepancies between the amount of water expected and the amount arriving could mean the difference between having water in the taps and entire towns drying up.

We are looking down the barrel of a gun loaded with our water resources in the West. Instead of investing in bulletproof vests, we hoped that the trigger would not be pulled. Current water monitoring and modeling strategies are not enough to support the growing number of people who need water. I am concerned about the coming week, month and year and the new issues we will inevitably face as climate change continues and water becomes more unpredictable.

It is time for policymakers allocating funds to invest in updating our water models instead of maintaining the status quo and hoping for the best. Large-scale investment in the agencies that maintain and develop these models is paramount in preparing for the future of water in the West.

Ultimately, better water models mean more accurate water management, and that will lead to greater water security and availability for the millions of people now dependent on changing water supplies. It’s an investment in our future, and moreover, an investment in our continued ability to inhabit the water-scarce regions of the West. It’s the only way to make sure we’re ready when the trigger is pulled.

Dr. Schwartz is the Principal Scientist and Station Manager at the Central Sierra Snow Laboratory at the University of California, Berkeley.

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