California Deluge Is Still Far Too Little to End Drought's Grip

(Bloomberg) -- For all the torrential rains soaking California, it’s not enough to end the drought that has dogged the state for years.

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The most optimistic case is a downward spiral of drought, though that depends on whether the downpours continue. The bundle of atmospheric rivers in the past couple weeks have caused widespread flooding and killed at least 14 people. While the deluge raises hopes of drought relief, there’s still a risk California could suffer a repeat of last year, when the state had its driest January-to-March period despite a flurry of storms in late 2021.

“While current storms have created a strong start to the wet season, we’re still in early January with over half the wet season to come,” said Jeanine Jones of the California Department of Water Resources. “Major reservoir storage remains below average, and conditions could turn dry again this winter, offsetting recent rain and snow.”

The rains are critical in breaking the worst period of drought in the US southwest in 1,200 years. The dryness has hurt crops across California’s Central Valley, one of the world’s largest agriculture economies, put large cities under stress, threatened water supplies for many smaller communities and contributed to some of the largest and deadliest wildfires in state history. Dwindling flow in the Colorado River bordering California has also put hydroelectric supplies in danger. California is coming off its driest three-year period since 1896, according to Jones.

“This has created a huge water deficit that will take time — and much more rain and snow – to erase,” Jones said in an emailed statement. “Groundwater levels in much of the state have also been depleted by the numerous dry years. It would take more than a single wet year for groundwater levels to substantially improve at the statewide scale.”

The next US Drought Monitor update, which comes out Thursday, may provide an early signal of just how much relief storms have offered to the parched lands in the most populous US state. California was 97.9% in drought through the last week, although the worst categories of dryness were improving, according to the last weekly update of water resources across the US. The Pacific storms have brought California within 80% of what it needs by April 1 to consider this an average year, which is vastly better than the past three years.

Even then, drought has left lingering challenges for California, according to Brad Rippey, a meteorologist with the US Department of Agriculture and co-author of the drought report. Years of pumping ground water has led to a collapse of underground chambers where water was held and the sinking of lands on the surface.

Those underground pockets “may never come back because of the nature of geology,” he said. “There has definitely been some damage to the ecosystem in terms of groundwater storage.”

While the latest storms aren’t seen to do much to dent California’s total drought, the weather has reduced the overall severity of the dryness. The state has seen the level of exceptional drought — the worst category — drop to zero in its Jan. 5 report, which was down from about 7.2% a week earlier and almost 17% three months before.

The western US is expected to get more rain and snow than normal through the end of January, according to Marc Chenard, a senior branch forecaster at the US Weather Prediction Center. An atmospheric river expected to land Thursday is likely to graze Northern California before moving into the Pacific Northwest.

All of which is a good start, but doesn’t necessarily mean it will lead to a strong finish, according to USDA’s Rippey.

“We’re doing a lot good in terms of drought easing, but we are not there in terms of drought eradication,” he said.

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