Drought conditions spread over state
Sixteen days into summer, with wildfires raging over the bone-dry landscape and more scorching hot days ahead, it might feel as if California is on the verge of another drought.
The official word from weather authorities shows much of the state trending in that direction.
Abnormally dry or drought conditions prevail over 85 percent of California, including the coast from Monterey County to the Oregon border, the U.S. Drought Monitor said Thursday.
Nearly all of Lake County and parts of eastern Napa and Mendocino counties are now in moderate drought, authorities said.
The coast of central and southern California, from San Luis Obispo County to the Mexican border, is in “severe drought,” with the state’s southeastern toe in “extreme drought.”
The contrast is stark with last year at this time.
In mid-2017, on the heels of a drought-busting rainy season, the same report listed 76 percent of California - encompassing everything north of Monterey County - free of drought or abnormal dryness. Abnormally dry and moderate drought conditions were mostly limited to a coastal strip running south from San Luis Obispo County.
This year, the outlook is more varied, with much of the Northern California coast and Sierra Nevada now categorized as abnormally dry. Wildland blazes have fed on those dry conditions, with more than 2,600 wildfires reported so far this year.
But reservoir levels remain much better off than in previous summers at this time. Ten of the state’s major reservoirs are holding nearly as much or more water than usual, with giant Lake Shasta at 79 percent full, equal to its historic average. Lake Sonoma and Lake Mendocino, the reservoirs that serve more than 600,000 Sonoma and Marin residents, are 89 percent and 73 percent of targeted capacity, respectively. Does this a drought make?
“This is definitely what you call a dry year statewide,” said Jeanine Jones, interstate resources manager for the California Department of Water Resources.
“We like to say one dry year is not a drought.”
The 2016-17 water year, the one that broke California’s five-year drought, was the second wettest on record in terms of statewide runoff, Jones said.
From one end of California to the other, rain or snow was above normal, including 166 percent of average in Santa Rosa and 138 percent in Ukiah, according to statistics compiled by Jan Null, a Saratoga-based meteorologist.
Most significant, he said, the northern Sierra Nevada, which fills several of the state’s largest reservoirs, had 173 percent of normal precipitation.
Santa Rosa recorded more than 60 inches of rain, soggy Cazadero had more than 101 inches and the dry inland town of Sonoma and nearly 51 inches, filling local reservoirs to the brim in late spring. But the 2017-18 season was a comparative bust, with total rainfall ranging from less than 30 percent down south to the 60 percent to 90 percent range in Northern California. Santa Rosa, with less than 25 inches of rain, was at 69 percent of normal; Ukiah at 63 percent.
Santa Rosa gets an average of nearly 36 inches of rain a year.
The Drought Monitor tends to overstate the case for California, Null and Jones said, because it is compiled in other parts of the country and framed largely from an agricultural perspective, with emphasis on recent rainfall.
It does not take into consideration the fact that California, with its Mediterranean climate, features perennially dry summers.
“We have a summertime drought by definition,” Null said. “We’re always sort of on the edge.”
The monitor is designed to measure the conditions on “unmanaged water systems,” such as ranching without irrigation, Jones said. “If you’re a rancher on grasslands that don’t get much rain you immediately feel an impact,” she said.
Urban and suburban residents, in contrast, are supported by systems like the Sonoma County Water Agency, which has a multi-year water supply, Jones said.
Joe Pozzi, a Valley Ford sheep and cattle rancher, said grasses and pastures normally go dormant in summer, just as ranchers are selling off calves and lambs. Adult animals get by grazing on dry land until rain returns. The situation only gets tense if storms don’t come soon enough. Last winter’s relatively skimpy rainfall has contributed to the rash of wildfires, sapping moisture from grass and brush that is now potent fuel, Cal Fire Deputy Chief Scott McLean said.
Firefighters have responded to 2,626 incidents since January, compared with 2,365 during the same period last year, he said.
The state needs several more years of abundant rain to boost the moisture content of vegetation, McLean said.