Stormy week brings Sonoma County rainfall close to normal

Heavy rain and thunderstorms that pounded the North Coast late Wednesday night and Thursday morning has allowed the region to play catch-up after an especially dry October, bringing season-to-date rainfall totals close to normal.

The storm brought rainfall since Oct. 1 to 6.10 inches at the Charles M. Schulz-Sonoma County Airport, compared to a 30-year average of 6.52 inches for the same time-frame, the National Weather Service said.

With months still to go in the rainy season, there’s no telling yet what the future may hold. But for now, the season’s offerings have arrived at just the right pace, forecasters said.

“This is the way we want to see it,” said Ryan Aylward, who works out of the Eureka office of the National Weather Service. “Not too much” at one time.

The potential for creek flooding and even surface flooding in low-lying areas are always a concern at this time of the year, and a few of those hazards surfaced during the commute hour Thursday morning.

But of particular concern, given the proliferation of huge, barren wildfire scars around the region, is the threat of mudslides and dangerous debris flows unleashed by abundant, pronounced rainfall.

The burn zone left by this summer’s Mendocino Complex fire, which burned across more than 410,000 acres in Mendocino and Lake counties, much of Forest Service land, is vulnerable to soil movement. No problems were reported Thursday.

Similarly, areas affected by the Tubbs and Nuns fires in Sonoma and Napa counties in October 2017 also remain at risk.

But emergency officials and others said there were no major incidents Thursday, beyond about ?13 downed trees throughout Lake, Napa and Sonoma counties, according to Cal Fire, and a few minor crashes, the CHP said.

There also were small mudslides on Pine Mountain Road east of Cloverdale and on St. Helena Road, northeast of Santa Rosa, said Dan Virkstis, public affairs program manager for the Sonoma County Department of Transportation and Public Works.

In such cases, one lane of roadway was open for travel in both directions, he said.

The bulk of the season’s rain has arrived over three storm periods, including Oct. 1 and 2, when about 1.23 inches fell at the county airport, weather service meteorologist Scott Rowe said. After more than a month of dry weather, more rain arrived last week, when 2.8 inches of rain fell at the airport from Nov. 21 to 23.

Wednesday and Thursday, the airport received 1.62 inches during the ?48 hours ending at 4 p.m.

“Those are helping tremendously to erase to-date rainfall deficits,” meteorologist Rick Canepa said. ?The heaviest rain the past two days fell in the tiny hamlet of Venado west of Healdsburg, where the gauge reached 3.5 inches.

Rain was likely to return tonight, bringing a quarter- to a half-inch of rain in the valleys and more in the coastal hills, with cooler temperatures through the weekend and a chance of rain returning Monday night.

The rainfall season runs from Oct. 1 to Sept. 30 each year.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.