Atmospheric river soaks Bay Area, forces evacuations in Russian River area

An atmospheric river brought additional rain, strong winds, and flooding to the Bay Area Tuesday, triggering evacuation orders for the area around the Russian River in Sonoma County.

In addition, the gusty winds caused thousands of power outages across the Bay Area, and tens of thousands of outages across the Pacific Gas and Electric Service area of Northern and Central California.

Evacuations in Sonoma County

Evacuation orders were issued early Tuesday evening along part of the Russian River in Sonoma County as the waterway is expected to swell from rain, the sheriff's office said.

The order is for low-lying areas from unincorporated Healdsburg to Jenner that are 36 feet below or under. The sheriff's office listed the following locations.

32 feet:  Lower Mill Street in Guerneville and Old Bohemian Highway in Monte Rio.
32.5 feet: In Guerneville the intersection of Highway 116 and Neeley Road is closed. Mays Canyon Road by the old rodeo grounds is closed.
33 feet - In Guerneville the intersection of Highway 116 and Drake Road is closed. In Monte Rio Willow and Alder Streets flood. In Forestville Mirabel Trailer Park begins to flood.
34 feet - In Guerneville flooding begins at Johnsons Resort, Parkers Resort, Creekside Resort and Riverside Park. In Northwood, lower Redwood Drive begins to flood.
35 feet - Numerous businesses and residences in the lowest sections of towns along the Russian River are expected to flood. In Guerneville Brookside Resort begins to flood. More extensive flooding occurs at Parkers Resort. In Northwood lower Redwood Drive floods.
36 feet - In Forestville, Mirabel Park Resort and Mirabel Trailer Park flood. In Guerneville, Fern Road at Highway 116 floods.

The sheriff's office said current forecasts expect the river to swell to 35.2 feet at Guerneville by 7 a.m. Wednesday.

Those who live above the 36-foot level will see their access be limited or completely cut off due to flood waters. There is a temporary evacuation point at the Santa Rosa Vet's Hall, west parking lot at 1351 Maple Avenue.

Those residents who are unsure whether they are under evacuation order can check this map online.

Sonoma County Schools additionally announced that all schools in the Guerneville School District and the Monte Rio Union School District would be closed due to the ongoing severe weather. 

Storm impacts

A severe thunderstorm warning was initially issued for Marin County and south central Sonoma County as a line of thunderstorms moved through at around 2:15 p.m. Tuesday afternoon. A second wider warning was issued for San Francisco, southern Marin County, and northern San Mateo County, and then extended to 4 p.m. due to winds gusting to 70 mph.  

The Weather Service said the thunderstorms were to bring widespread torrential rain and wind gusts expected to damage trees, mobile homes, roofs, and outbuildings. 

In San Francisco, a mudslide happened around 6:20 p.m. at Sansome and Union streets. The San Francisco Fire Department said no injuries were reported and asked the public to avoid the area. There is no threat to public safety.

At Golden Gate Park, a downed tree blocked three lanes near Crossover Drive and Lincoln Way. Delays were expected.

In Santa Rosa, the Sutter Urgent Care Center on Airway Drive was shut down because of flooding in the parking lot. Five wheelchair-bound patients, who were there for day appointments, were evacuated. Firefighters brought in a paratransit van to help them. There were also two stuck in a car surrounded by floodwaters who also needed help.

The parking lot on Airway Drive has flooded before in past storms.  

In Saratoga, part of Highway 9 will be temporarily closed beginning at 3 p.m. Tuesday, Caltrans said. The closure will be from Sanborn Road to Redwood Gulch Road. Emergency vehicles and residents will be allowed to pass through the closure.

Caltrans said crews will remove mud and debris from the regraded slope on Highway 9. The reopening of the roadway is tentatively scheduled for 6 a.m. on Wednesday. The weather could affect the reopening time. 

The Santa Rosa office of the CHP posted photos at 2:40 p.m. showing flooding on U.S. Highway 101 south of Windsor that had completely shut down northbound lanes of the highway. In the photos, cars were backed up in both directions.

The flooding closure happened at the Arata Lane exit. Southbound 101 is partially open, but only passable on the shoulder. Officials were able to reopen the affected lanes in both directions shortly after 3 p.m.  

CBS News Bay Area reporter Wilson Walker confirmed that a mudslide swept a Forestville home into the Russian River near the Forest Hills Bridge Tuesday afternoon.

Walker posted photos of the mudslide that destroyed the home, leaving debris piled at the side of the still-rising Russian River. The address of the house was 12354 Westside Rd. The small town along the Russian River is located in Sonoma County.

KPIX First Alert Weather: Current conditions, alerts, maps for your area

Earlier Tuesday, the Weather Service said in its daily forecast discussion that the Bay Area was "now in the cross-hairs of the atmospheric river" and rain along the leading edge of the storm front was spreading from the North Bay south across the region to the Santa Cruz Mountains.

North Bay flood concerns

The rain triggered flood warnings in Sonoma County, one which replaced an earlier flood advisory for the central portion of the county, now in effect until 10 p.m. Wednesday. The Weather Service said some of the locations that will see flooding include Santa Rosa, Rohnert Park, Windsor, Sebastopol, Cotati, Larkfield-Wikiup, Forestville and Graton.  

The warning indicated that flooding of rivers, creeks, streams, and other low-lying and flood-prone locations was imminent or occurring. Streams and other waterways were expected to keep rising because of the excess runoff from earlier rainfall. Low-water crossings were being inundated with water and may not be passable, the Weather Service warned.

"As the cold front moves through during the day Tuesday, the rain rates will increase significantly as the cold, dense air mass lifts the warm, moist air mass, wringing out the atmospheric sponge," the forecast discussion said. "This effect will be enhanced along the windward side of the coastal mountains."  

A flood advisory was also issued until 4:45 p.m. for Point Reyes Station, San Geronimo, Tomales, Dillon Beach, Stinson Beach, Muir Beach, Tamalpais-Homestead Valley, Inverness, Lagunitas-Forest Knolls, Woodacre and Bolinas.  

Meanwhile, Green Valley Creek at Martinelli Road in Forestville and Mark West Creek near Mirabel Heights were rising to moderate flood stage, expected by Tuesday night. Flood advisories for urban and small stream flooding were also issued for the North Bay, San Francisco, and the northern East Bay, said the Weather Service.

Rainfall rates in San Francisco have been as high as over half an inch per hour since Tuesday morning, and the amount of rain was expected to increase throughout the day. Heavier bands of rain pushing through the Bay Area were also triggering reports of urban and roadway flooding, the Weather Service said.

Strong winds whip through Bay Area

Wind gusts were strong Tuesday across the Bay Area, and even stronger in higher elevations as well as in the Monterey Bay region. A wind advisory was in effect Tuesday until 11 p.m. for the East Bay and San Francisco Bay shoreline, Santa Clara Valley and eastern hills, the Santa Cruz Mountains, and the Central Coast, in addition to the Salinas and Carmel Valleys and Hollister Area.  

Wind gusts across the Bay Area were peaking at about 50 mph and above. An 80 mph wind gust was recorded on Pine Mountain Fire Road west of San Anselmo.

As of 3 p.m. Tuesday, about 27,000 PG&E customers in Northern and Central California were without power. 

"We're starting to enter the peak risk period in terms of rain, winds and the associated outages," said Jake Zigelman, vice president of PG&E's Bay Area region, during a press briefing. "So we expect that to ramp up over the course of the day and into the evening." 

In the Bay Area, there were 3,429 customers without power on the Peninsula, mostly in Pacifica, Colma, Daly City, Montara, Moss Beach, and El Granada, according to PG&E spokesperson Tamar Sarkissian. In addition, 3,816 customers in the North Bay and about 1,000 East Bay customers were enduring outages as of Tuesday afternoon.

The wind also apparently led to major delays on the BART system. The agency reported that debris on the trackway near Colma station was causing 20-minute delays on the San Francisco airport line in the Millbrae and East Bay directions.

The combination of strong winds and moist soils will increase the risk of downed trees and power outages, the Weather Service said.  

Thunderstorm outlook

The Weather Service earlier advised of a 10% or greater chance of thunderstorms for the Bay Area and Northern Monterey Bay regions through Tuesday evening. Before the severe thunderstorm warning was issued for the North Bay Tuesday afternoon, the service said the most probable window for thunderstorms was from 3 p.m. to 6 p.m. south of San Jose.

Thunderstorm hazards include lightning, small hail, gusty winds and localized flooding. There was also a chance of water spouts off the coast, the Weather Service said.

The storm was expected to break on Wednesday but another moisture plume and low-pressure system was expected to arrive at the coast and push inland on Thursday, although it appeared weaker than the current atmospheric river.

The Bay Area will dry out again on Friday and as clouds start to clear over the weekend, the overnight lows could drop back into the 30s in some parts.

Bay City News contributed to this report.

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