Novato slide triggered by ‘bomb cyclone’ threatens utilities
Marin picked up the pieces after another powerful storm slammed into Marin, triggering a mudslide in Novato that threatened water and gas lines that distribute throughout the county.
The Tuesday night landslide destroyed a section of Redwood Boulevard north of the city that runs adjacent to Highway 101. The slide caused a large segment of the road to buckle, blocking access to Olompali State Park and bending a PG&E power pole.
The “bomb cyclone” storm that ripped through the county on Tuesday resulted in downed trees into homes and widespread outages that left areas of Woodacre and Sausalito especially hard hit. The swirling low pressure system deepened quickly, increasing wind speed. Tuesday broke the all-time record for the lowest barometric pressure ever recorded in March at San Francisco International Airport.
The rare event killed three people in the Bay Area. Falling trees killed a homeless man in Oakland near Lake Merritt, an elderly man sitting in a car in the Walnut Creek community of Rossmoor, and a man driving a truck in Portola Valley.
Dial Hoang, a meteorologist with the National Weather Service, said in the 48-hour period ending at 5 p.m. on Wednesday, some parts of the county received nearly two and a half inches of rain.
San Rafael received 1.66 inches; Mount Tamalpais received 2.40 inches; Novato received 2.41 inches; Mill Valley received 1.98 inches; Point Reyes Station received 1.71 inches and Kentfield received 2.09 inches.
High wind speeds topped out at 68 mph on Wolfback Ridge; 58 mph near Nicasio; 55 mph near Woodacre; 51 mph near Marinwood; 53 mph near Novato and 45 mph near Point Reyes Station.
Flooding was also reported adjacent to the Highway 1 and Highway 101 interchange near Mill Valley, Hoang said.
Jeff Whittet, a battalion chief with the Novato Fire District, said the slide was first reported at 7:25 p.m.
Between 75 and 100 feet of a nearby hillside fell 20 feet down the hill, severely damaging Redwood Boulevard near Buck Center Drive in Novato. The slide buckled the asphalt and undermined the road with liquid and mud, rendering the road impassable. The slide also displaced a power pole, leaving about 150 customers without power.
Whittet said the power was back on as of Wednesday afternoon. Officials, including a 24-hour security team, remain at the site, which is closed to the public. There is no loss of services at this time, he said, though officials are still evaluating the impacts to water and gas lines.
Megan McFarland, a spokesperson for PG&E, said two underground gas transmission lines were affected by the slide. One was exposed at the top of the mudslide and one is buried in the slide.
PG&E cannot visually assess the second buried pipeline and has reduced operating pressure on it.
“Safety remains our first responsibility,” she said. “We immediately dispatched a PG&E crew to the scene, notified local first responders and worked together to assess the situation and make the area safe. At this time, we have identified no risk to the general public and do not anticipate a disruption to gas service.”
The landslide also occurred near the main aqueduct pipeline that transports Russian River water to Marin County’s two largest water suppliers, Marin Municipal Water District and North Marin Water District.
Marin County fire Battalion Chief Todd Overshiner said the gas lines feed all of Marin County.
Overshiner said county emergency and fire officials were required to shut down one of the gas lines.
“If they had to shut down both they will have to shut down gas to all of Marin County,” he said. “As far as I know, they have not had to go to that extreme.”
North Marin Water District General Manager Tony Williams said the slide did not damage the water pipeline, but that the pipe has been shut off as a precaution.
“In case the slide got worse or was to move and destroy the pipe we didn’t want thousands and thousands of gallons of water gushing into Highway 101,” Williams said.
Williams said there is currently no estimate on when the pipeline will be turned back on. The district is waiting to begin any work until PG&E clears a PG&E power pole that was bent as a result of the slide. Williams said they’re hoping the county will begin coordinating with PG&E and Caltrans.
“We’re good in the short term but there would be other factors where we would need to turn that back on,” Williams said.
Marin Municipal Water District communications director Adriane Mertens said the agencies will be shutting down its Ignacio treatment plant, Ignacio boosters and the North Redwood pumps for at least the next week.
“The district has also deployed mobile generators to pump stations that could be impacted by temporary power shutdowns,” Mertens wrote in an email. “Marin Water is actively working to finalize temporary operations plans, which will likely include greater reliance on the San Geronimo Water Treatment Plant in San Rafael.”
Elsewhere in the county, Overshiner said there were reports of downed trees and power lines, including on San Geronimo Valley Road in Woodacre.
Ross Valley fire Battalion Chief Gavin Illingworth said a new mudslide was reported on Bolinas Road. The slide added to a slide that had occurred from a previous storm, he said.
Illingworth also said there were new reports of trees down on Cascade Drive and Buena Vista Drive in Fairfax.
In Southern Marin, Battalion Chief Doug Paterson said the department was fielding reports of downed trees, but said the day was “moderately quiet” compared to Tuesday.
Forecasters said dry weather is expected Thursday through Sunday, with another storm system possible next Monday.
“Things will dry out,” said Alexis Clouser, a meteorologist with the National Weather Service. “Enjoy it.”
Bay Area News Group contributed to this report.