Sonoma County sees wettest January in two decades as new storm arrives

This January has been the wettest start to a new year in Santa Rosa since 1995, with 15.11 inches falling since Jan. 1 and more on the way this weekend.

In all, Santa Rosa has seen 34.82 inches of rainfall since October - 1.5 inches shy of the city’s historical average for an entire season, with eight months still left in the rain year.

Steve Anderson, a forecaster with the National Weather Service, said Sonoma County would likely pass that mark by Sunday, when another heavy band of rain is set to make landfall.

From Wednesday night into Friday morning, about 7 inches of rain fell in the hills west of Healdsburg - typically the rainiest spot in the region, where more than 2 feet of rain has fallen this month.

Since Wednesday, 5 inches has fallen in Cloverdale, 4.5 inches in Santa Rosa, and about 2 inches in Petaluma and along the Sonoma Coast, Anderson said.

Some rural roads were flooded Friday and seven remained closed as a result of damage or debris. They included Trenton Road between Laguna Road and River Road, Mark West Station Road at Starr Road, and Todd Road between Old Gravenstein Highway and Llano Road.

The last time the North Bay saw a January like this, 22 years ago, Santa Rosa recorded just over 17 inches of rain in a torrential El Niño winter that pushed the Russian River to 48 feet in Guerneville - 16 feet over flood stage - submerging 1,400 homes and businesses, and causing over $56 million in damages.

Last week’s storm, while not nearly as devastating, still swelled the river to just under 38 feet in Guerneville, flooding dozens of homes and roads throughout the rest of the county.

Rain is expected to return to the region Saturday night, intensifying through Sunday, with Santa Rosa expected to get up to 4 inches through the weekend, and winds of 20 to 40 mph.

The Russian River is set to crest at 6 a.m. Monday at 28.6 feet, about 3 feet under flood stage.

On Friday, Lake Sonoma was at 123 percent of seasonal capacity, and Lake Mendocino at 125 percent of target water supply storage, said Brad Sherwood, with the Sonoma County Water Agency.

The Army Corps of Engineers dramatically cut the amount of water released from the reservoirs overnight Thursday and into Friday, as heavy rain fell and the Russian River rose, said the Army Corps’ Mike Dillabough.

As of midnight Jan. 20, the release from Lake Sonoma dropped to 292 cubic feet per second from 2,459 cfs on Thursday morning.

At Lake Mendocino, it declined from 1,025 cfs to 300, Dillabough said.

“We’re saving Guerneville from getting about 6,000 additional acre-feet of water per day,” he said. “(The river) would be 6 inches to a foot higher. The last thing we want to do is flood anybody.”

You can reach Staff Writer Christi Warren at 707-521-5205 or christi.warren@pressdemocrat.com. On Twitter @SeaWarren.