opinion | California’s drought is worse than we thought

Outside my lab near Donner Pass in the Sierra Nevada mountains of California, new animal tracks appear in the snow after a hibernation, birdsong soars through the air, and the creek flows strongly with water from the melting snow. Spring has arrived worryingly early in the Sierra Nevada.

Over the past week, I’ve joined teams of other scientists who have been collecting key measurements of Sierra Nevada’s snowpack at over 265 locations across the state. Typically, this measurement marks the transition from the snow accumulation season to the melting season and contains the most snow of any measurement year-round. However, the 2022 results confirmed what those of us monitoring the state’s drought had feared: California’s snow cover is now at 39 percent of its average, or 23 percent lower than at the same time last year. This signals a deepening drought – already the worst in the western United States in 1,200 years – and another potentially disastrous fire season for much of the West.

Many people have a rather simplistic idea of ​​drought as a lack of rain and snow. That’s right – to a certain extent. What it doesn’t take into account are human activities and climate change, which are now having a dramatic impact on available water and its management. As more frequent and larger wildfires and extended droughts ravage the country, our key water management tools are becoming increasingly inaccurate. At the same time, it is becoming increasingly problematic for us to rely on these models to try to make the most of the little water we have.

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

It would take many storms with near-record amounts of rain or snow in a single year to significantly impact drought conditions. October was the second snowiest and December the snowiest month since 1970 on snow labs, thanks to two atmospheric flows hitting California. But the exceptionally dry periods of November and January through March have given us another year of below-average snowpack, rain and runoff conditions.

These types of fast-or-hunger winters, with large storms and long, severe dry spells, are expected to increase as climate change progresses. As a result, we will need several years of above-average rain and snow to make up the difference, rather than consecutive major events in a single year.

Even with years of normal or above-average precipitation, changes in land surface pose another complication. Massive wildfires, such as those we’ve seen in the Sierra Nevada and Rocky Mountains in recent years, are causing marked changes in the way snow melts and water , including rain, runoff from the landscape. Loss of the forest canopy to fires can result in higher wind speeds and temperatures that increase evaporation and reduce the amount of snow water reaching the reservoirs.

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Similar to prolonged drought, fire also alters soil properties and can lead to flash flooding during periods of intense rain. These landscape changes, feast-or-starvation rainfall patterns, and increased water supply demands make water management in the West a precarious and difficult task.

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

Land surfaces, snowmelt 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 the models from being updated for decades is the shrinking funding for science and technology.

Models may not be able to reliably inform water managers of how much rain and snow is being run off land into reservoirs, leading to severe bottlenecks at worst. With falling water levels in reservoirs and meager snow cover in recent years, discrepancies between expected and incoming water volumes could mean the difference between water taps and entire cities drying out.

We’re looking down the barrel of a loaded gun with our water resources to the west. Rather than invest in body armor, we hoped the trigger wouldn’t get pulled. Current water monitoring and modeling strategies are insufficient to support the growing number of people in need of water. I worry about the next week, month and year and new problems we will inevitably face as climate change continues and water becomes more unpredictable.

It’s time for policymakers to allocate funds to invest in updating our water models, rather than maintaining the status quo and hoping for the best. To prepare for the future of water in the west, significant investment in the authorities that maintain and develop these models is paramount.

Better water models ultimately mean more accurate water management, and that will lead to greater water security and availability for the millions of people who now depend on changing water supplies. It is an investment in our future and, moreover, an investment in our continued ability to inhabit the arid regions of the West. It’s the only way we can ensure we’re prepared when the trigger is pulled.

dr Schwartz is a senior scientist and station manager at the University of California, Berkeley’s Central Sierra Snow Lab.

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