Will rain end California’s drought?

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A friend recently asked me, “Is this the end of the California drought? It’s been raining all week!” A valid question to ask after such an extended period of rain. Surely, the logic seems to follow. If California is suffering from a lack of water, then it makes sense that rain would be the solution. 

Officially classified as a “bomb cyclone” due to its rapid strengthening, this storm has certainly lived up to its name. Highway 70 suffers from tremendous damage due to landslides which now block roads. Heavy rain over burn scars such as the one from the Dixie Fire triggered mudslides and debris flow. To top it off, Downtown Sacramento broke the all time record for 24 hour rainfall at 5.44 inches, previously sitting at 5.28 inches from 1880. And unsurprisingly, Sacramento’s record-breaking rainfall occurred shortly after its longest dry spell on record — all to say, California is going through the wringer.

Fortunately, there are some positives as reservoir and lake levels rise in response to the heavy rainfall. This is broadly a welcome sight due to fire season and overall drought reduction. But the question remains: What does this all mean in terms of California’s drought?

While it may seem reasonable to assume that the drought has ended, the rapid shifts between droughts and floods are yet another symptom of climate change. Previously, California experienced a rapid transition from multiyear dryness between 2012 and 2016 to extreme wetness during the 2016-2017 winter. This week’s record-breaking rainfall after an extended period of drought is a microcosm of an ongoing shift in California’s climate. 

Daniel Swain, lead author and climate scientist at UCLA, recently published a paper in 2018 outlining the “weather whiplash” that California suffers from. Titled “Increasing precipitation volatility in twenty-first-century California,” Swain and colleagues explain California’s future using the Community Earth System Model Large Ensemble of climate model simulations. 

A Mediterranean climate, like that of the Bay Area, has characteristically dry summers and wet winters. Thus, California’s ecosystem is generally able to withstand these shifts in precipitation or lack thereof. However, the increasing frequency and intensity with which these swings happen can endanger plants and animals that fail to adapt. Swain points to widespread Sierra Nevada tree mortality and unsuitable water temperatures for migrating salmon as drastic examples. The damage climate stress has and will inflict upon California’s ecosystems continues to put pressure on efforts to curb climate change. But it is not only plants and animals who are in danger. The risk of severe flood events that are projected to increase by 300 to 400% would put incredible stress on our flood management system. If a weather event similar to Great Flood of 1862 were to happen, millions of lives would be put in danger as the few dams and canals in the California flood plains are pushed to their limits.

But to give a definitive answer to the question, these unprecedented levels of rain seen in the past few days are not an end to California’s drought, but are in fact a warning of what’s to come: longer droughts, stronger storms and heightened danger for plants, animals and humans.

Contact Adrian Fontao at [email protected].