California is most likely heading into a fourth consecutive year of drought.
The state’s water year ends tomorrow, which has prompted predictions about what’s in store for the next 12 months. (California’s water year runs from Oct. 1 to Sept. 30, so that the winter rainy season falls within a single water year.)
The forecasts tend to agree: The Golden State’s extreme drought, exacerbated by warming temperatures and increasingly unpredictable precipitation patterns, is expected to continue into the new year. Gov. Gavin Newsom warned on Wednesday that Californians must adjust to a hotter and drier world.
“As the state prepares for the possibility of a fourth dry year and potential weather extremes, it’s more important than ever that all of us adopt water conservation as a way of life,” Newsom said in a statement. “Together, we can save water and save California.”
Many of the state’s water providers have already instated unprecedented restrictions this year, and Californians are increasingly ripping out their thirsty lawns. But the state’s water supplies are still more depleted than we would hope.
The past 12 months were cooler and rainier than the prior year, and many of California’s biggest reservoirs are fuller than they were a year ago, John Yarbrough, the assistant deputy director for the Department of Water Resources, told the California Water Commission last week. While that’s good news, reservoir levels are still well below average, he said. It’s “better than last year, not good enough,” he said.
California typically gets 75% of its annual rainfall between November and March, a feature of its Mediterranean-type climate. That concentrated wet season means that a few months of low rain can have a major impact on the state’s water availability for the year.
This winter, weather officials are predicting La Niña conditions for the third year in a row. Like its climatological cousin El Niño, La Niña is a weather phenomenon that originates in the Pacific Ocean but can affect the whole world.
In California, La Niña generally means less rain than usual, particularly in the southern two-thirds of the state, said Brad Pugh of the National Weather Service Climate Prediction Center. It’s always possible that this La Niña could beat the odds and bring heavy storms, “but right now, the most likely outcome is for below normal precipitation this winter,” Pugh said.
And even if this winter were to be exceptionally rainy, the state’s water problems are probably too severe to reverse in a single season, experts say.
The land is so parched that when it does rain, the plants and soil will absorb more rain than they would otherwise, limiting how much ends up in rivers and streams. Warmer temperatures mean precipitation is more likely to fall as rain instead of snow, so it can’t be stored as easily for the summer. Not to mention that the Colorado River, a major source of water for Southern California, is in dire shape, said Alex Hall, the director of the Center for Climate Science at U.C.L.A.
“We need a really terrific water year, and probably even maybe a couple of pretty amazing water years, to get us out of this hole,” Hall said.