6 Santa Rosa properties affected by soil slide; 2nd atmospheric river to wallop North Bay Monday night

Forecasters, on Sunday, advised North Bay residents to keep their umbrellas handy heading into the work week as another atmospheric river was expected to dump even more rain onto the region starting Monday evening.

Predictions of more rain do not bode well for the occupants of at least six properties along Cooper Drive in Santa Rosa, including several homes and a synagogue, that were affected Sunday by soil movement on a nearby hillside, according to the Santa Rosa Fire Department.

Fire officials said the city “red-tagged two Cooper Drive properties and worked with those residents to find alternative accommodations until conditions improve.”

Authorities were also monitoring “the slide mass behind three additional properties ... but no actions” were taken by the city as of the fire department’s 4:30 p.m. post on social media.

The department added that “both the city and Congregation Shomrei Torah have engaged geotechnical engineers to evaluate the conditions and placed plastic sheeting and sandbags to protect against further rain infiltration into the soil to slow the slide mass movement.

“Once access to the area is safe and weather conditions have improved, the city will begin to remove the slide mass to reduce the current threat and work with property owners to evaluate the next steps,” fire officials said Sunday.

The first atmospheric river, which inundated parts of Sonoma County over the weekend, dropped more than 3 inches locally before gradually tapering off Sunday afternoon.

Precipitation totals from this weekend exceeded meteorologists’ predictions.

Besides the anticipated 3 inches the National Weather Service predicted, the accumulation recorded on Sunday added another 0.10 of an inch to 1.5 inches of rain to Sonoma County’s overall rain totals, according to the weather service’s weather and hazards data viewer.

Valley locations received 0.10 of an inch in Petaluma to about 0.90 of an inch in Healdsburg. And, Santa Rosa, as of 4:35 p.m., had received about 0.70 of an inch.

More rain was expected in the higher elevations, according to NWS meteorologist Eleanor Dhuyvetter.

Dhuyvetter said that while the daily rain tallies on Sunday were small, there were reports of nuisance flooding and at least one mudslide, near Guerneville.

“We are seeing some more mild to moderate impacts just from these lower amounts because the ground is already so, so saturated,” she said.

The next powerful storm system, a second atmospheric river, will arrive late Monday, said Brooke Bingaman, a Monterey-based meteorologist for the National Weather Service.

Sonoma County can expect 2 to 3 inches of rain in the valleys, and from 3 to 5 inches in the highlands. A flood watch, along with a high wind watch, will be in effect from late Monday evening through Wednesday morning.

As happens when one major storm follows so closely on the heels of another, “the impacts are going to be a bit compounded,” said Bingaman.

“Because the soils are already super saturated, any additional rainfall is basically going to be straight run-off into our streams and river systems. So we’re definitely concerned about flooding.”

Predicted high winds could also contribute to more storm-related hazards, such as downed trees, Dhuyvetter said.

The weather service issued a high wind watch for Monday night into Tuesday night for the parts of the Bay Area and Central Coast.

Wind gusts reaching up to 40 mph in the Sonoma County valleys and about 50 mph in higher elevations could cause multiple trees, already sitting in soaked soils, to topple, Dhuyvetter said.

After cresting at 28.26 feet late Friday -- just below “monitor level” – the Russian River at Guerneville is now forecast to reach 29.5 feet on Wednesday at about 9 am, according to a chart produced by the California Nevada River Forecast Center, whose predictions come with significant margin for error.

That would be half a foot above the “monitor” level and about 2.5 feet below the flood stage.

The Russian River is expected to crest at about 15.5 feet in Hopland at about 2 pm Tuesday -- half a foot beyond its 15-foot flood stage, at which water can flood crop lands near the river and flow into Highway 175.

You can reach Staff Writer Austin Murphy at austin.murphy@pressdemocrat.com or on Twitter @ausmurph88.