Atmospheric River Arrives: Healdsburg, Sonoma County Under Flood Watch

HEALDSBURG, CA — Healdsburg residents were urged to be prepared as an atmospheric river storm began bearing down Thursday on the North Bay and the Bay Area, and is expected to last into Friday, bringing floods and thunderstorm hazards.

A flood watch was implemented for the entire region from Thursday afternoon until Sunday morning. A wind advisory was expected to remain in effect until Friday afternoon.

Gov. Gavin Newsom declared a state of emergency to support storm response in 21 counties, including Napa. Sonoma County was among 13 counties last week where a state of emergency was already declared.

"Widespread wetting rains are expected over the district through Friday as a potent atmospheric river moves over California," the weather service said. "The moderate to heavy rain will bring increased flooding concerns and landslide potential. In addition to the rain, gusty southerly winds will persist through Friday. Winds will be strongest near the coast and higher terrain."

Over 2 Inches of Rain Reported In Sonoma County

Most cities in the Bay Area observed at least a tenth of an inch of rain in the past 24 hours, as of 4 p.m. Thursday. The North Bay has seen the most rainfall, with many cities observing more than half an inch of rain.

By 6 p.m. Thursday, the National Weather Service reported 12-hour rainfall totals of more than 2 inches for several parts of Sonoma County, including Graton, Occidental, Cazadero, Sebastopol, Monte Rio, Bodega Bay and Austin Creek/Russian River.

Rohnert Park received 1.90 inches of rain by 6 p.m., Healdsburg received 1.37 inches and Petaluma received 1.10 inches.

Roadway Flooding Reported In Sonoma County

As of 5 p.m. Thursday in Sonoma County, the California Highway Patrol reported a rockslide with mud, dirt and rock on westbound River Road just east of state Highway 116; flooding on westbound Occidental Road east of SR-116 and on Hall Road west of Fulton Road in Santa Rosa; a tree blocking northbound Dry Creek Road south of Lytton Springs; and a mudslide with trees attached on Green Hill Road at Graton Road.

Russian River Flood Outlook

According to the National Weather Service, rainfall and snowmelt will lead to rapid rises of area rivers, streams, and creeks. Rivers with the most significant flooding potential are Napa, Russian, Salinas, Pajaro and Carmel.

In Sonoma County, the Russian River was forecast to reach the "monitor stage" of 29 feet Friday afternoon at Johnson's Beach near Guerneville. The river's flood stage is 32 feet. The current forecast indicates the river will crest at 30.9 feet Friday night at Johnson's Beach near Guerneville. Thursday afternoon, the river was at 12.6 feet.

Flooding is not currently expected on the Russian River in Healdsburg. The river is expected to reach 16.7 feet Friday morning, whereas the monitor stage for the Russian River in Healdsburg is 20 feet and the flood stage is 23 feet.

The Napa River near Napa was forecast to reach "monitor stage" of 22 feet Friday morning. The river's flood stage is 25 feet. The current forecast Thursday afternoon indicated the river would crest at 22.1 feet Friday afternoon, according to the California Nevada River Forecast Center.

In preparation for possible flooding, the city of Napa on Thursday closed the Oxbow flood gates along the Napa River at McKinstry street.

"Flooding is an extremely serious concern associated with this AR," the weather service said. "The ground is already saturated and streams/rivers are already swollen. When additional heavy rainfall falls on an already saturated ground the only thing it can do is run off. Streams/rivers will be quicker to flood due to their current capacity."

The City of Healdsburg issued a weather update Thursday:

At this time, it is *not* anticipated Healdsburg will reach flood stage.

A Flood Watch means “Be Prepared,” and is issued when conditions are favorable for a specific hazardous weather event to occur. It does not mean flooding will occur, but it is possible.

In addition to the Flood Watch, a Wind Advisory will be in effect from 1 p.m. today until 4 p.m. Friday.

Downed trees and power outages could occur – please exercise caution, especially while driving, and secure or fasten loose objects.

ALWAYS assume a fallen power line is live, and NEVER touch a downed power line, or any object touching a fallen power line!

The City of Healdsburg’s sandbag fill station is available at the Healdsburg Community Center (1557 Healdsburg Avenue).

Sand and empty bags will be provided, however we recommended you bring:
- A shovel to fill bags
- Gloves to protect your hands
- A helper to assist in filling

For more information on how to fill and use sandbags, visit healdsburg.gov/390/Storm-Water, and scroll down to "Resources."

For more information on flooding, visit healdsburgemergency.org.

For flooding, downed trees that are not blocking a roadway, or power outages, please call the City’s 24/7/365 Emergency Utility Hotline at (707) 431-7000 or toll free (855) 755-6586.

For emergencies that pose a threat to life and/or property, such as a downed power line, or downed trees blocking a roadway, always dial 9-1-1.

For information on Reach for Home's Winter Shelter, please visit reachforhome.org/get-help.

Our team will continue to monitor the situation, and will provide updates if conditions require.

This is a developing story; refresh the page for the latest updates.