California has been on an amazing roller coaster of drought and floods recently.
The three years from 2020 to 2022 were the driest three-year period in the state’s recorded history, breaking the old record set during the previous drought from 2013 to 2015, according to the state Department of Water Resources.
But after a deluge this winter, reservoirs are full. Wildfire risk has dropped. Groundwater tables in many areas have risen. The Sierra snowpack, the source of 30% of California’s water supply, was at 324% of normal on Thursday, the highest level in 40 years.
The extreme swings have been documented each week in color-coded maps issued by the U.S. Drought Monitor, a weekly report by the NOAA, the USDA and the University of Nebraska.
Here’s how it unfolded: The drought began with below-average rain and snow in the winter of 2019-2020. It worsened the following winter as high-pressure ridges off the West Coast relentlessly blocked storms. By the summer of 2021, 95% of California was in “severe drought.”
Gov. Gavin Newsom declared a drought emergency in July 2021 and asked Californians to cut urban water use 15%. Cities imposed restrictions on lawn watering. Farmers in many areas received little or none of the water they had hoped for from federal and state projects, forcing them to fallow fields and increase groundwater pumping. Wildfires raged, from the Santa Cruz Mountains to Lake Tahoe to Sequoia National Park.
One of the more alarming symbols came at Lake Oroville, California’s second largest reservoir, where on Aug. 5, 2021, water levels fell so low — to just 24% full — that the power plant had to be shut down for the first time since it opened in 1967.
In Marin County, the largest water agency came within six months of having its reservoirs go dry, and frantically planned to build a $100 million emergency pipeline over the Richmond-San Rafael Bridge to import water from the East Bay.
A wet December that year raised hopes that the drought might be ending, only to see them dashed when the driest January, February and March in a century occurred in early 2022. By that summer, reservoirs had dropped to dangerously low levels.
Many experts were planning for a fourth year of severe drought this year. It would have meant severe water rationing in many areas. But a series of more than a dozen very powerful, drenching atmospheric river storms soaked the state. They began shortly after Christmas and continued into mid-January.
A few more such storms arrived in March. The storms caused damage — killing at least 20 people statewide, and wrecking roads and buildings in coastal areas, including Capitola Village, which President Biden toured afterward to promise federal help. They also filled reservoirs, created the biggest Sierra Nevada snowpack in 40 years and ended the drought.
Last month, Newsom announced that the State Water Project would provide 100% of water deliveries to cities and farms for the first time since 2006. He lifted drought restrictions. And although some areas, particularly in the San Joaquin Valley, still have low groundwater levels, many are from decades of over pumping by farmers. Meanwhile, there is so much snow that concerns about Central Valley flooding remain high as the Sierra snowpack continues to melt and the summer nears.
Although people often say that severe droughts can’t end in one year, many of California’s worst droughts, including the 2012-16 drought, ended with one very wet winter.
The latest was no different. In December, 80% of the state was in severe drought, according to the U.S. Drought Monitor. Barely three months later, by early April, none was. With climate change, many scientists say California should expect more “weather whiplash” — grueling droughts broken by parades of atmospheric river storms.
Will the wet conditions continue this upcoming winter? Or will another drought start? Nobody knows. But El Niño conditions are emerging in the Pacific Ocean, with waters warming along the equator. And in strong El Niño years when ocean waters are very warm, the chances of wet winters in California go up.
