Environment & Science

California measures the Sierra Nevada snowpack amid dry winter

File: The snow survey tube sits in the snow placed there by Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources, after conducting the manual snow survey at Phillips Station, Thursday, March 30, 2017, near Echo Summit, Calif.
File: The snow survey tube sits in the snow placed there by Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources, after conducting the manual snow survey at Phillips Station, Thursday, March 30, 2017, near Echo Summit, Calif.
Rich Pedroncelli/AP

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Amid record-setting heat in the state's south, California's water managers measured the Sierra Nevada snowpack, which supplies water to millions.

Department of Water Resources officials trekked to the mountains Thursday to check the snow depth, one gauge of the state's water supply. Snow levels are about one quarter of normal.

"It's not nearly where we'd like to be," Frank Gehrke, a state official, acknowledged after carrying out manual measurements of winter snowfall in the Sierra Nevada mountains.

Statewide, the snowpack was at about 27 percent of the average for this date. Last year, the Februrary snowpack measurement was 174 percent of normal, said Doug Carlson, Department of Water Resources spokesman.

“You can see what a dramatic shift the weather has made since last year,” Carlson said.

At the peak of California's recently ended five-year drought, Gov. Jerry Brown ordered 25 percent water conservation in cities and towns and declared a drought emergency.

Heavy rains in Northern California last year finally snapped the drought, and Brown declared the emergency over in April.

But the drought never really seemed to end in some Southern California areas, said Daniel Swain, a climate scientist with the University of California, Los Angeles.

Los Angeles received only one significant rain in almost the last 12 months.

In Ventura and Santa Barbara counties, which are about 100 miles north of Los Angeles, the lack of rain and dry vegetation were perfect fuel for a December wildfire that grew to be the largest recorded in state history. When it finally rained, the scorched earth turned into deadly mudslides.

The most recent weekly U.S. drought monitor, a product of the federal government and others, shows only small patches of the state, in Southern California, in the mildest form of drought. That compares to 2014 and 2015, some of the driest years in history in California, when much of the state was rated as in the most severe categories of drought.

In the middle of the state's winter rain and snow season, no rain is in the forecast. In Southern California, "it really is pretty grim," said Swain, who has tracked the stubborn weather patterns blocking rain from the state's south for years.

Carlson, spokesman for the state's Department of Water Resources, which carries out the snowpack surveys, said the dry weather is a growing concern, although reservoirs are still fuller than usual thanks to last year's rain in Northern California.

Considerations of what constitutes a drought vary, and include: rainfall, the state of waterways, soil dryness, and other measures. Any decision to declare a new drought emergency if the winter remains dry, or later, would be up to Brown.

If this winter ends without a generous snowpack up north, Southern California’s large water agencies will use the bumper supply of water they saved from last year’s record rain and snow.

The L.A. Department of Water and Power used excess water from the Owens River last year to replenish storage reservoirs and percolate water into underground aquifers. That water can be pumped out and sent south on the L.A. Aqueduct in the coming year.

The LADWP also expects to buy more water from the Metropolitan Water District, said DWP Sr. Assistant General Manager Richard Harasick. MWD imports water from Northern California and the Colorado River.

Thanks to last year's wet winter, Metropolitan stored a record 1.2 million acre feet. That’s enough to supply the region for a couple of dry years. In a single dry year, the agency would draw down 100,000 to a half-million acre feet, said Metropolitan Senior Engineer Demitri Polyzos.

An acre foot is about what three families would us in a year. Despite that buffer, Polyzos said Southern Californians cannot  take the stored supply for granted.

“We need everyone to do their part and conserve and to continue to conserve. That is how we're going to get through potentially dry consecutive years,” Polyzos said.

This story has been updated.