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Amid record heat in Southern California, fears of new drought

Rong-Gong Lin II, Los Angeles Times on

Published in Weather News

The water content in the northern Sierra Nevada snowpack was only 30 percent of normal for this time of year; a year ago, officials recorded it at 182 percent.

"It shows, once again, California's great variability -- it has the greatest weather variability in the country," said Doug Carlson, spokesman for the California Department of Water Resources. "It's not encouraging -- but it's nothing to wring your hands over yet."

A big problem has been the rising temperatures in the Sierra Nevada. Though more storms have come to the north than the south, warmer temperatures have caused precipitation to fall as rain instead of snow.

That means that precipitation can't be stored as snow in the mountains during the winter and later banked in the reservoirs when it melts in the spring and summer. Right now, the reservoirs are mostly as full as they can be, as they still have leftover surplus from last year's record season, while still keeping enough empty space available behind the dams should an unexpected flooding event happen.

Carlson said officials are not panicking about the small snowpack, given the time left in the winter, but "all this adds up to keeping a watchful eye to where the rest of the wet season goes."

The snowpack on average supplies about 30 percent of California's water demands as it melts in the spring and summer.

Even the storms that have hit the Sierra are nothing like what the region saw last year. "In the Sierra, we had 10 strong 'atmospheric rivers' that affected the northern and central Sierra last year," said Chris Johnston, meteorologist with the National Weather Service's Reno office. "This year we've had very weak atmospheric rivers, and the strongest one was probably back near Thanksgiving." Even that one was just moderate.

The National Weather Service's Climate Prediction Center, which issues three-month outlooks for precipitation and temperature, doesn't have particularly good news. For February, March and April, the center is forecasting probable drier-than-average precipitation and hotter-than-average temperatures for Southern California.

One silver lining for California's cities and farms is that the reservoir system can help get the state through a dry year. "But we never know what's coming next year," Swain said.

 

And there is no reservoir system for California's wilderness.

"That has really profound impacts on California's forest, where there has been tremendous mortality in recent years," Swain said. The U.S. Forest Service has estimated that more than 102 million drought-stressed and beetle-ravaged trees have died across 7.7 million acres of California forest since 2010 -- unprecedented in the recorded history of the Sierra.

"If we see another low snow year, that's probably going to continue ... especially in the southern half of the state," Swain said.

(Staff writers Melissa Etehad and Sarah Parvini contributed to this report.)

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