Heavy California rains have bright side: relief from drought

Heavy rains in California have led to more than a dozen deaths and widespread destruction, but they are also providing at least temporary relief from the historic drought that has plagued the state.

Over the past two weeks, California has seen torrential rain as well as snow, causing power outages and putting thousands of people under evacuation or shelter-in-place orders. However, the degree to which the series of storms will make a long-term difference to the state’s drought is more of an open question.

“It’s definitely too early to say we’re out of the drought, so to speak,” said Andrew Ayres, a researcher at the California Water Policy Center’s Public Policy Institute. But, he added, it has been a “really good start” to the year in terms of precipitation and snow.

The wet weather is expected to continue for at least a few more days. Overall, at least 19 people had died as of Friday, and about 400,000 were without power at some point during the downpour.

On Friday, the US Drought Monitor said only 0.32 percent of California was under “extreme drought,” down from 27 percent of the state last week and 41 percent last month.

“We have seen improvement in drought conditions,” said Andrea Bair, a meteorologist with the National Weather Service. “We’ve increased soil moisture and built those mountain snows even further into above-normal conditions.”

But, Bair said, “we have a long-term drought that has been going on in much of the West for years.”

“Reservoir deficits are large, very deep soil moisture deficits, significant groundwater depletion,” she added. “Those kinds of things take longer to get over and fully recover from.”

For years, much of the western United States, including California, has been subject to significant drought, which has been exacerbated by climate change. The drought has damaged agriculture, public health and even energy resources in the region.

Last year was the ninth driest on record in California.

The state’s ongoing drought has caused crop changes, forcing farmers to switch out almost all trees in favor of less water-intensive crops. It has also contributed to wildfires and reduced populations of fish species.

Ayres noted that more water could enable irrigation supplies for agriculture and looser lawn irrigation restrictions. If the water problem were to be alleviated in the long term, it could also mean less spending on expansion projects or water purchases, which could ultimately lower water bills.

Bair said there will be a clearer picture of the long-term impacts of precipitation in April, once impacts on snow have been fully measured.

Felicia Marcus, former chairwoman of the California Water Resources Control Board, said snow is even more important than rain in mitigating drought because it will melt over time, saving extra moisture for later.

“The snowpack is the brass ring … because the beauty of the snowpack is that you get moisture, but you get it with a benefit of time,” said Marcus, who is now a visiting fellow at Stanford University.

“As you start using your reservoirs, it melts in the spring to summer and it recharges the reservoirs, it recharges the streams, and it can be measured on a time scale that can help recharge the groundwater more efficiently,” she added.

Marcus said that in terms of the overall drought, the state is off to a great start to the year so far, but it remains to be seen if it will continue to play out.

How much rain the state receives is also only part of the picture; how it is managed is also important.

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Ayres said it is especially important to ensure that excess water that may appear now is put into storage — that is, by pumping surface water into underground basins.

He said obstacles to such efforts could include obtaining regulatory permits for removing water from flooded rivers and dumping it on land or reaching complicated agreements between water systems and agricultural irrigation areas.

“Preparing all the infrastructure and institutions to be able to capture this water is really important,” Ayres said, noting that this will be even more true going forward as climate change exacerbates extreme weather.