Dry season with summer fast approaching renews drought threat in Sonoma County

Battered by fires, flooding, power outages and a mass evacuation in recent years, Sonoma County residents now have to brace for revival of the D-word - for drought.

Beneath the rolling green hills and blooming spring flowers lies a grim recollection of the most recent five-year drought, which ended in 2016.

Sonoma County experienced a bone-dry February, a first in the area’s history and the nadir of a rain season, now nearly over, that has given Santa Rosa just 18 inches of rain - well over a foot shy of the nearly 34-inch average for this time of year. Last year, the city had about 44 inches of rain at this time.

Only three places in Sonoma County currently have at least 20 inches to date. Most locations had from 30 to more than 60 inches of precipitation a year ago,

There’s a skimpy chance of rain this weekend, but long-range forecasts see no precipitation for the rest of the month or in June, when Mother Nature’s tap typically turns off.

Joe Pozzi, a west county sheep and cattle rancher, paused for a beat to ponder the drought question.

“I would say yes,” he said. “Just because of the little amount of rain we’ve had.”

Farm ponds haven’t filled due to lack of runoff this spring and his livestock are eating the grass as fast as it sprouts.

“Usually by this time of year the grass is growing faster than the animals can consume it,” Pozzi said.

The nation’s drought sentinel concurred.

More than one-third of California (36%) was in moderate or severe drought, the two lowest of four drought designations, the U.S. Drought Monitor said last week. Sonoma County and most of the Bay Area were in a band of moderate drought that looped into the Central Valley and reached the Nevada border.

A band of severe drought extended from Oregon down to the northern parts of Mendocino and Lake counties and had, in just the previous week, swelled from a small bulge into Siskiyou County. It could spread farther south in the two nearby counties, said Brian Fuchs, a climatologist at the National Drought Mitigation Center who compiles the Drought Monitor.

Nearly 13% of the state was in severe drought last week, jumping up from just 1.3% the previous week. About 23% of the state was designated abnormally dry last week, which is not considered drought.

A year ago, there was no drought in California with a 6% portion abnormally dry at the southernmost end of the state.

Three months ago, the state was also drought-free with a 6% abnormally dry patch at the northern tip of California.

Adding to the weather anomaly this year, a tongue of moderate drought that had reached Los Angeles in mid-March retreated north of the San Luis Obispo and Kern county lines last week, driven out by record-breaking rain that left the entire southland free of drought and abnormally dry conditions.

The result was an “upside-down” rain season, with a wet south and a dry north, reversing the usual polarity, Fuchs said. “Typically, Northern California is the wetter part of the state,” he said.

Most of Southern California recorded 800% of normal precipitation in just the last week and 200-400% of normal over the last 30 days,” the Drought Monitor report said last week.

In sharp contrast, rainfall in Sonoma County ranged from about 45% to 55% of normal for the season through Tuesday, according to a California Nevada River Forecast Center map. The lone outlier was at Venado in the hills west of Healdsburg, which had 94% of its normal 51 inches for season.

The regional drought, Fuchs said, is already impacting areas that get no water from reservoirs, including range lands, forests, pastures and non-irrigated cropland.

National Weather Service meteorologist Rich Canepa said “it would be tough to make up the deficit” at this point.

Jay Jaspers, chief engineer at Sonoma Water, the agency that supplies Russian River water to about 600,000 Sonoma and Marin county residents, said there has been no official drought emergency declared in the Bay Area or Sonoma County.

The North Bay has had “very low rainfall,” but the agency’s two major reservoirs - Lake Sonoma near Healdsburg and Lake Mendocino at Ukiah - are both in good shape, Jasperse said. Lake Mendocino holds 18% more water than usual due to an effort to improve coordination of storm forecasting and flood releases, he said.

Northern California’s three major reservoirs are currently near or at their historical average level.

The Sierra snowpack, which stores about one-third of California’s water supply, was well below average early this month.

About 75% of the state’s precipitation occurs from November to March, with half of it in December, January and February.

You can reach Staff Writer Guy Kovner at 707-521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.