Water worries not over

New snowpack measurements from the Sierra Nevada released Wednesday dashed hopes that California’s stormy winter would make a significant dent in the state’s water supply woes.

The measurements found that snowpack levels have returned to average because of a dry March. Wet weather beginning in November sent snow levels far above average, prompting officials to hope that conditions would continue into spring and provide more water.

But California is back in familiar dry mode.

After briefly experiencing above-average rainfall in December and January, the state is back in the negative column thanks to a very dry March.

Downtown Los Angeles has recorded 13.39 inches of rain since July 1, 0.13 inches short of a normal year. Burbank has had 13.51 inches in the same period, 1.93 inches short of normal.

“You realize we do live in a desert,” said Bonnie Bartling, a National Weather Service specialist.

“Some years you get some and other years you get nothing.”

Bartling and others said they doubted that any last-minute record deluges would change the pattern before the end of this rain season in July.

Southern California has experienced a record dry period, with less than 4 inches of rain falling in downtown L.A. during the 2006-07 rain year.

But the local drought is only one reason for the region’s water woes.

Southern California depends heavily on imported water, about half from northern mountain snowpack and the rest from the drought-stressed Colorado River. Further straining supplies, a court decision protecting a rare fish in the Sacramento-San Joaquin River Delta has reduced water deliveries to the south by 30%. To comply with court stipulations, state officials last week cut southward flow for seven days by 75% of normal.

Until recently, officials were hoping that a big snowpack would ease the shortage.

“We had a very productive January and February, but there’s been virtually no storm activity in March,” said Frank Gehrke, chief of the California Cooperative Snow Surveys. “We’ve lost some of that advantage. But if we didn’t have January and February, we’d have long faces.”

Measurements showed that snow levels were at 105% in the northern Sierra, 89% in the central Sierra and 103% in the southern Sierra -- an area that includes water that’s sent to L.A. A 100% reading would mean levels were average.

The eastern Sierra, responsible for much of L.A.’s water, came in just under 100%, Gehrke said.

For management of the state’s reservoirs, the snow is measured five times a year.

Last month, snow levels were at 122% in the northern Sierra, 110% in the central Sierra and 130% in the southern Sierra, Gehrke said.

The recent “warm weather is not good for the snowpack,” said Bill Patzert, a climatologist with the Jet Propulsion Laboratory in La Canada Flintridge. “You want to see it linger and melt slowly through the spring.”

The early deluge helped Southern California approach normal rain totals for the year.

Bartling emphasized that this year’s rainfall was a vast improvement from 2007. Downtown, for example, had recorded only 2.47 inches of rain by this time last year.

And the snowpack levels were dire 12 months ago. Statewide levels were at 48%, compared with 97% today.

As summer draws closer, the chances of any sustained rain dwindles. Gehrke said there were “storm opportunities” in the Sierra Nevada next week.

But a storm predicted for Wednesday fizzled.

Meanwhile, the weather in the L.A. Basin is expected to remain dry in the coming days. Temperatures will remain in the low 70s and high 60s, Bartling said.

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david.pierson@latimes.com