California’s dry fall extends fire danger and deepens water worries

The longer that California waits for its early-season rain, the more its roughly 40 million residents will have to confront the risk of catastrophic wildfire, not to mention dropping reservoirs and parched farm fields.

And this year is a clear example of that pattern, with deadly wildfires burning at both ends of the state and scant rainfall since autumn began eight weeks ago.

In the North Bay, the dry spell hasn't shattered any records. The 1.23 inches of rain that have fallen since Oct. 1 in Santa Rosa make it only the 62nd driest October on the books since 1902.

But since that pair of rain days early last month, the storm door has slammed shut, producing mostly warm, sunny, walk-in-the-park days that felt good but generated a mounting sense of unease in a state only one winter removed from a historic five-year drought.

The nights have turned chilly in Sonoma County, but even those who rely on burning wood to heat their homes are reluctant to strike a match for fear of sending sparks over the arid woodlands.

“They're just nervous about it,” said Eric Miller, owner of a Santa Rosa wood stove store who lives in Occidental. “I'm hearing it more and more.”

State firefighters, observing fog-free mornings and wildfire fuels virtually bereft of moisture, worry that an inferno like the Butte County catastrophe could strike close to home.

“It sets us up so something bad can happen,” said Marshall Turbeville, a Cal Fire battalion chief.

Sonoma County is hardly alone.

The latest map by the Western Regional Climate Center shows the county - and the vast majority of the state - received no more than 50 percent of average precipitation from Oct. 1 through Monday. In many places, including the northwest corner of Sonoma County, it is far lower - 5 to 25 percent - and in some bands, including the East Bay and South Bay, it's 5 percent of average or less.

Santa Rosa, since Oct. 1, has registered about 40 percent of normal rainfall.

The good news?

Thanksgiving may bring something from the skies to be thankful for, with rain possible on Turkey Day.

Some of the National Weather Service's computer models say rain will fall from Oregon to Monterey on Thanksgiving and move on the following day to deliver precipitation from Monterey to Southern California.

It's unclear exactly when or how much rain will fall, or whether more moisture will follow, forecaster Steve Anderson said.

But if it comes, he said, the southwest wind preceding the storm front will blow away smoke from the Butte County fire that has lingered over the Bay Area since Thursday, when the Camp fire erupted.

“I think we've had enough,” Anderson said, referring to the foul air from the most deadly and destructive wildfire in state history.

The wind would push the smoke into Nevada, Oregon, Idaho and Canada, he said.

The prolonged dry spell is due to a persistent ridge of high pressure over the West Coast that has shoved storms into Canada, Anderson said.

Accuweather, a private forecasting service, shows “rain and drizzle possible” Tuesday, with rain or showers also “possible” the next three days.

“That would be great,” said Tony Crabb, a Healdsburg-area wine grape grower.

The harvest is over and the vines, now shutting down for the winter, could use a bit of water before they go dormant, he said. “Give them a drink before they go to bed.”

Crabb said he had to truck in water to replenish his irrigation pond for the grapes and to protect the huge, 40-year-old catfish and German mirror carp it sustains.

“Old friends,” he called them.

Vineyards could also use a dose of rain to stimulate the post-harvest cover crop that adds nutrients to the soil, said Karissa Kruse, Sonoma County Winegrowers president. “It's a win-win,” she said.

For the record, October and November are not always rain-stingy.

Over the past decade, counting this year, Santa Rosa has received as much as 7.66 inches and as little as 0.01 inches of rain from Oct. 1 to Nov. 14, according to Accuweather.

For October alone, Santa Rosa ranges from 7.57 inches in 2016, a drought-busting year, to zero in 2013.

October is “a bit of a wild card month” in California, with rain numbers that “pretty much hinge on whether or not we get one significant storm,” Daniel Swain, a UCLA climate scientist, said in an email.

But when a dry spell stretches into mid-November it becomes “drastically more unusual,” he said, especially in Northern California. Vegetation is still at peak dryness and the offshore winds are nearing their peak in many places, Swain said.

“This, indeed, is extraordinary - and means the fire season will continue at full blast until widespread wetting rains finally occur,” he said.

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