Sonoma County officials warn of flood risk in burn zones as winter storm arrives

A torrential storm that swept into Sonoma County Tuesday night was expected to peak early Wednesday, bringing with it the risk of flooding, debris flows and other dangers to areas still recovering from recent wildfires.

No evacuation warnings were in place in Sonoma County on Tuesday evening, though residents living in and around the burn scars created during the Walbridge, Glass and Meyers fires last year, as well as the 2019 Kincade fire, were cautioned to be ready to leave if the downpour expected early Wednesday created unsafe conditions.

Late Tuesday night, the National Weather Service issued a flash flood watch for parts of west Sonoma County that were affected by the Walbridge fire. The warning was set to expire at 11 p.m. Residents of the area were advised not to travel unless ordered to evacuate because of the risk of localized flooding.

A separate advisory warned of localized flooding in creeks and small streams. Heavy rain could overwhelm drainage in some areas of the eastern part of the county, including parts of Santa Rosa.

Rainfall of about an inch per hour would be needed to trigger debris flows within the local burn scars, thought the county wasn’t expected to exceed that threshold during the height of the storm, Sonoma County Director of Emergency Management Chris Godley said Tuesday afternoon during a briefing with other Sonoma County and Santa Rosa officials.

Still, residents with heightened concerns were encouraged to seek refuge elsewhere overnight until the brunt of the storm passed, Sonoma County Fire District Chief Mark Heine said during the meeting.

“If you’re concerned about the area that you live in because you live in the footprints of these fires … do not wait for us to evacuate you,” Heine said. “Leave now.”

Showers began to roll into Sonoma County Tuesday afternoon, though the heaviest rain was expected to come early Wednesday morning in the form of an atmospheric river, said Brooke Bingaman, a meteorologist with the National Weather Service.

Snow was recorded in Sonoma County’s highest peaks and had the potential to continue falling at elevations greater than 4,000 feet in the northeastern edge of the county into Tuesday night, Bingaman said.

In Mendocino County, heavy snow and falling trees closed Highway 101 in both directions north of Laytonville on Tuesday night, cutting off the region’s main route to Humboldt County and the North Coast, state Sen. Mike McGuire tweeted.

The atmospheric river, an intense moisture-laden storm front, has the potential to bring a half-foot or more of rain to Sonoma County, making it the wettest storm of the winter so far.

It prompted the National Weather Service to issue a flash flood watch that covered much of the Bay Area, including Sonoma County, beginning Tuesday into Thursday afternoon.

The threat of debris flows prompted evacuation orders in Santa Cruz and San Mateo counties Tuesday for areas burned by wildfires last August, as well as an evacuation warning for residents in Napa County living near fire-impacted areas.

A high wind warning that signaled gusts of up to 60 mph was also issued and is expected to last into Wednesday afternoon, the weather service said. The strongest winds were expected to coincide with the periods of heaviest rain.

“You’ll see the brunt of the storm overnight,” Bingaman said. “The peak winds will also be arriving with that heaviest rain.”

Sonoma County officials, including those in the cities of Petaluma and Santa Rosa, issued warnings about the impending storm via Nixle and other online platforms Tuesday afternoon.

The Santa Rosa Emergency Operations Center was activated Tuesday afternoon so city workers could respond to any weather-related emergencies that sprouted overnight, among them debris flows, downed trees and power outages, officials said.

Neighborhoods of most concern within the city limits were those in the Calistoga North, Calistoga South, Skyhawk, Pythian, and Melita evacuation zones, the alerts said.

“Don’t hesitate to call if something doesn’t feel or look right,” Santa Rosa Assistant Fire Marshal Paul Lowenthal said.

Additionally, a strike team made up of five fire engines and 20 firefighters was stationed in Santa Rosa to assist with emergencies throughout the county, said Heine, the county fire chief.

Pacific Gas & Electric Co. crews were staffed up in Sonoma County starting Tuesday through Thursday to respond to outages brought on by the storm and strong winds, company spokeswoman Deanna Contreras said.

“With the wind, we are expecting to see … tree limbs or trees falling into our power lines,” Contreras said. “We are ready to respond to outages as safely and quickly as possible.”

Foothill Regional Park, which was torched during the Kincade fire, putting it at risk of debris flows and landslides, will be closed through at least Friday. Damage could lead to a longer closure, park officials said.

Sugarloaf Ridge State Park above the Sonoma Valley and the Laguna de Santa Rosa trailhead west of Santa Rosa near Highway 12 will also be closed until further notice.

Visit www.pressdemocrat.com for updates Wednesday morning.

Staff Writer Kaylee Tornay contributed to this report. You can reach Staff Writer Nashelly Chavez at 707-521-5203 or nashelly.chavez@pressdemocrat.com. On Twitter @nashellytweets.