In California, the Snow Tells the Future for the Water Supply
Max Whittaker for The New York Times
Frank
Gehrke, center, has led snowpack surveys in California for a
quarter-century. The state's multibillion-dollar agricultural industry
pays close attention.
PHILLIPS,
Calif. — Along Highway 50 in the Sierra Nevada, elevation 6,820 feet, a
California winter ritual unfolded here on a recent morning. In the
snow-blanketed meadow of a local homeowner's backyard, reporters
representing news organizations from across the state followed a man on
skis who kept plunging an aluminum tube into the snow.
Leading
the pack was Frank Gehrke, California's chief snow surveyor, the man
responsible for measuring the Sierra Nevada's snowpack, the source of a
third of this state's water supply. Part groundhog, whose appearances
signal the shift of the seasons, and part Federal Reserve chairman whose
utterances on the state of the snowpack can move California's
multibillion-dollar agricultural industry, Mr. Gehrke has led the
Department of Water Resources' snowpack surveys for a quarter-century.
In the state that is home to Silicon
Valley, Mr. Gehrke and his team use the stick-the-tube-into-the-snow
method developed by a local classics professor more than a century ago.
"There've been only incremental
changes," Mr. Gehrke said, interspersing this winter's second monthly
survey with a veteran's calm observations of the snowfall and hints of
the possible coming drama that is California's annual snowmelt. "This
course is very uniform, which is normal, because the snowpack during
accumulation is kind of uniform. But once you start getting into the
melt, it starts to go crazy."
His
assessment of this month's survey — after a strong start, the snowpack's
water content fell to 93 percent of average for this time of the year
because of a "midwinter lull" — was carried on television channels
throughout the state. Pictures of Mr. Gehrke, grasping the tube with his
gray mittens against a backdrop of the Sierra Nevada, appeared on the
front page of newspapers in Sacramento and the Bay Area.
In
California's water system, one of the world's most sophisticated and
complex, the snowpack plays a leading role by supplying water to more
than 25 million people and almost one million acres of farmland. Snow
that accumulates on the Sierra Nevada's 400-mile range starts to melt in
the spring, draining into rivers that feed reservoirs below.
As
Mr. Gehrke and his team gauge the depth and water content of the
snowpack, other department officials begin forecasting how much water
the snowpack will be able to deliver this year.
Those
who depend on the snowpack for water adjust their plans accordingly.
Water districts may start looking for water elsewhere or carry out
conservation measures. Farmers consider the forecasts in deciding what
crops to plant or whether to take bank loans to buy more seed and
equipment for the year.
Ryan
Jacobsen, who is executive director of the Fresno County Farm Bureau and
also sits on the board of the Fresno Irrigation District, said that the
snow surveys are the "bible for what decisions irrigation districts are
going to make for the rest of the year."
"Fresno
County is the No. 1 agricultural county in the nation, but we also
happen to be situated climatically in the middle of a desert," he said.
"It really is the Sierra Nevada snowpack that makes this desert bloom."
It was in 1908 that James E.
Church, a classics professor at the University of Nevada, Reno,
developed the existing method of forecasting water runoff from the depth
and water content of snow. To settle a dispute over water rights in
nearby Lake Tahoe, he was able to predict the water from the snowpack on
Mount Rose by using a hollow tube that he called the Mount Rose snow
sampler. Government agencies adopted his technique and, in 1929,
California passed a law mandating that state officials measure the
Sierra Nevada snowpack and issue forecasts of the water supply.
"You
can almost say it made the development of the West possible," Mr.
Gehrke said. "Prior to that, they really didn't even have tools to use
to hope to predict how much runoff they would have."
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