By Don Ford

SANTA ROSA (CBS SF) — After a brief respite, another potent storm front approached the Bay Area Thursday, triggering a flash flood watch for the 77,758-acre burn area of the massive Kincade Fire and a prediction of as much as 4 inches of rain in the North Bay hills.

The brunt of the storm will target the Russian River area of Sonoma County, where waterways are already swollen from nearly a week of rain.

“Given the dynamics with the potent cold front and ample moisture, rainfall intensity will be of concern across the North Bay, especially in the Kincade Burn area,” the National Weather Service said. “Hourly rainfall rates could exceed one half an inch in an hour leading to debris flows or flash flooding.”

Along Highway 128 Thursday afternoon, contract crews were racing to place straw waddles around storm drains and along highway culverts and ditches, trying to protect the soil from washing away.

Sonoma County Board of Supervisors Chairman David Rabbitt said the county is doing its best to prepare.

“Behind us, all the work that we’re installing is to keep all the ground intact, so it doesn’t move,” said Rabbitt. “We have patrols from our county Public Works Department in the area, making sure that they’re watching out for any kind of movements or debris flows or slides.”

Toxic runoff from destroyed homes is another concern. Some homes are on steep banks of nearby creeks and streams.

“You know, we’re worried about the contaminates spreading. So we are using burlap waddles, sand bags, we’re using plastic and we are using Jute netting to stabilize the hillside,” said Paolo Tantarelli, the owner of Community Soil Landscape Contracting.

There were still many fire-damaged trees needing removal that might otherwise fall into roadways. Crew used giant chippers to grind entire logs into sawdust

Just down the road, many of the burned hillsides are being sprayed with hydro-seed, a fertilized mixture of grass seeds and binders that will help hold the soil in place. But the Kincade Fire burned more than 127 square miles, leaving too much ground to cover before the rains hit. The county is bracing as best it can.

“Knock on wood, we did well last week. We hope we do well this week,” said Rabbitt.

Forecasters said much of the Bay Area will get up to an inch of rain by the time the storm clears on Saturday. But other areas will experience steady downpours.

“Rainfall totals from Friday into early Sunday range from 0.50″-1.25″ in most urban areas, except 1.50-2.50″ in the North Bay Valleys,” the weather service said. “In the hills/mountains, rain totals are forecast to range from 1.50″-4.00″ in the North Bay Mountains, 1.25- 1.5″ for the East Bay Hills, 1.50-3.00″ in the Santa Cruz Mountains.”

On Thursday, no rain was predicted for Bay Area for the first time in several days. The region’s last tangle with an atmospheric river — pulling moist air from north of the Hawaii islands to the California coast — left some impressive rain totals.

According to the National Weather Service, Santa Rosa received more than 5.50 inches of rain over a 72-hour time span. St. Helena got 3.56 and Venado in the North Bay was pounded by 11.80 inches.

In the Santa Cruz Mountains, Ben Lomond recorded rainfall totals of 5.63 inches.

The brunt of the previous storm front has borne by areas of Monterey County. Over a 72-hour time span, Big Sur had over 9 inches of rain and over 8 inches fell on Three Peaks.