Sierra snow survey points to dry year ahead

The Sacramento BeeJanuary 3, 2014 

One month into winter, and it looks a lot like summer all across California.

The state is experiencing one of the driest starts to winter ever recorded, proven by the clear blue skies and record-warm temperatures that have persisted over the past few weeks.

How dry is it? The depth of the problem was exposed in plain terms Friday when the California Department of Water Resources conducted its first Sierra Nevada snow survey of the season.

Surveyors reported the snowpack is 20 percent of average across the mountain range that serves as a crucial water bank for the state.

In the central Sierra, which drains into Stanislaus, Merced and San Joaquin County rivers and reservoirs, the snowpack is at 21 percent. In the northern mountains, home to the state’s largest water storage reservoirs, the snowpack is 10 percent of average.

So it appears this is going to be California’s third-straight drought year.

“While we hope conditions improve, we are fully mobilized to streamline water transfers and take every action possible to ease the effects of dry weather,” DWR Director Mark Cowin said in a statement. “And every Californian can help by making water conservation a daily habit.”

Even more concerning to state water providers is the forecast. The National Weather Service this week predicted California likely will see below-average rainfall for the entire month of January.

That means the state is likely to emerge from winter with two of its wettest months essentially missing.

“Fortunately it was extremely cold for a few weeks through mid-late December or the (snowpack) survey would have been even more draconian,” said Jeff Shields, general manager of the Southern San Joaquin Irrigation District.

“Finding the tools to protect the biological integrity of our watersheds, while preserving agricultural production and the economic vitality of California, is going to be a challenge in the weeks and months ahead,” Shields warned Friday. “Equitable solutions will require creativity, cooperation and compromise – something we haven’t had a lot of in most of our discourse lately.”

Numerous California drinking water and irrigation districts already are planning for mandatory reductions in water flows.

“The current water situation will most likely mean a reduction of the water available to our irrigation customers for the 2014 irrigation season,” Turlock Irrigation District spokesperson Michelle Reimers said. “TID monitors the hydrological conditions on a 24/7 basis, so the snow conditions were not a surprise.”

The Modesto Irrigation District also is watching the situation. But John Davids, MID’s civil engineering manager, said it is too soon to say whether the district will have to reduce its water allocations.

The region’s water reservoirs, however, are relatively low.

The Don Pedro Reservoir, which serves both MID and TID and flows into the Tuolumne River, was only filled to 51 percent of its capacity as of Friday.

New Melones Reservoir, which serves the Oakdale Irrigation District and SSJID and flows into the Stanislaus River, was at 43 percent capacity.

Lake McClure, which serves the Merced Irrigation District and flows into the Merced River, was at 23 percent capacity.

Streams and rivers across California also are depleted.

According to gauges maintained by the U.S. Geological Survey, only 25 percent of the 215 monitored streams had “normal” water flow as of Friday, and 71 percent were below normal. About 21 percent are at unprecedented lows, a number that has doubled in the past two weeks.

These stream flows are crucial not only for fish and wildlife, but also for cities and farms that draw water from them.

“The big reservoirs that provide a lot of the state’s water, they’re not going to get a lot of recharge unless things really turn around,” said Alan Haynes, acting hydrologist in charge at the California-Nevada River Forecast Center, a branch of the National Weather Service in Sacramento. “It could happen, but chances are it’s not going to recharge the reservoirs a whole lot and then we’ll be starting from a low point next summer.”

The lack of precipitation is caused by an enormous and persistent area of high pressure parked over the Gulf of Alaska for months. It has detoured the normal storm track far north of its usual route through California, leaving the state stormless.

“We do have quite a few (storm) systems lined up there out in the Pacific,” said Michelle Mead, warning coordination meteorologist at the National Weather Service in Sacramento. “All those systems have been diverted to the north of us.”

It is unclear why that high-pressure ridge has persisted. It may be a result of a phenomenon called the Pacific Decadal Oscillation, which is like a larger and longer-lasting version of the ocean temperature phases that occur during El Niño and La Niña years. As the name implies, this particular cycle can lock in place for years and even decades.

The PDO is currently negative, meaning the northern Pacific Ocean is cooler than average. Bill Patzert, a climatologist at the NASA Jet Propulsion Laboratory in Pasadena, said droughts in California often are associated with a negative PDO. He argues that California is in the midst of a decades-long drought that began in 2000.

“The negative PDO tends to look like this,” Patzert said. “It tends to keep those Pacific storms quiet and certainly out of California. If there’s anything intelligent to forecast, it certainly looks like more of the same.”

The National Weather Service reports that a couple of storms may break through the high pressure and reach California on Tuesday and Thursday. But they are expected to be weak by the time they reach the state, and bring little if any precipitation.

Then the high pressure is projected to strengthen all over again.

Daniel Swain, a doctoral candidate in climatology at Stanford University, has been studying the situation and reporting about it on his blog, weatherwest.com. He said the high-pressure ridge has been in place since December 2012. After examining relevant weather records dating to 1948, he believes such a persistent ridge has never been seen before.

“It’s at least unprecedented in the observational record in that particular region,” said Swain, who earned his bachelor’s degree in atmospheric science at UC Davis. “I definitely think it’s a significant event.”

But some Stanislaus County water officials are more optimistic.

“I haven’t given up hope yet. I think we’re going to get some rain,” said Frank Clark, Oakdale Irrigation District board chairman. He nevertheless expects OID will have to reduce water allotments.

“We’ve lived through droughts before, and we’ll live through this one,” Clark assured. “But everyone will need to cooperate.”

Water agencies that depend on the Sacramento-San Joaquin Delta, a collection point for Sierra snowmelt, also could see shortages this year, especially farmers.

The state’s Department of Water Resources estimates it will be able to provide its 29 water contractors with 5 percent of the water they requested for 2014. That could change if the winter gets wetter, but that doesn’t seem likely right now.

Those water contractors serve 25 million people and 1 million acres of farmland between San Jose and San Diego.

“The state’s agricultural areas will see major impacts as the lack of water will result in the need to fallow important farmland,” Terry Erlewine, general manager of the State Water Contractors, said in a statement. “These conditions are worse than some of the most devastating droughts our state has ever seen.”

Modesto Bee staff writer J.N. Sbranti contributed to this report. She can be reached at jnsbranti@modbee.com or (209) 578-2196.

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