PG&E weather monitors might limit power shutoffs
Expanded equipment provides more information on conditions
When rough weather hits, like last week’s windstorm that brought gusts of more than 60 mph to parts of Marin County, Pacific Gas and Electric Co. is better equipped to spare customers from power shutoffs, the utility said.
Over the past year, the utility has expanded its network of weather monitoring equipment to 1,000 stations and 340 high-definition firewatch cameras across its service area. In Marin, that includes 21 weather stations, six of which were installed last year, and 12 cameras, three of which are new.
The weather stations collect data on wind speeds, humidity and temperatures. The cameras are strategically placed in areas that are elevated or are known for high fire risk, said Deanna Contreras, a PG&E spokeswoman.
In 2020, the additional equipment helped keep the power on for approximately 800,000 meters systemwide during questionable weather, Contreras said.
It takes special factors for a planned power outage, Contreras said. It’s a combination of wind above 25 mph with gusts stronger than 40 mph; humidity below 20%; a “red flag warning” by the National Weather Service; and fuel moisture.
The weather service has criteria of its own for calling a red flag warning, meteorologist Matt Mehle said. Similar to PG&E’s criteria, they include wind speed, relative humidity and fuel moisture.
“The windstorm that we just experienced, we had the wind criteria, but the piece that was missing was the fuel moisture,” Mehle said. “We saw some early season rainfall that the fuel moisture was high enough that we weren’t concerned
enough to call a red flag warning.”
Mehle said the expansion of PG&E’s weather monitoring equipment is impressive.
“It’s definitely a benefit on a larger scope to have more observations across the state,” he said.
In Marin, weather stations are scattered across the county. The newest cameras were installed in Bolinas, on Black Mountain in the Point Reyes National Seashore and at the Muir Beach Overlook. Cameras
were already installed on Mount Barnabe, Big Rock Ridge, Mount Vision, Mount Tamalpais, Mount Burdell and Wolfback Ridge.
“Having these cameras have been a huge asset,” said Mark Brown, executive officer of the Marin Wildfire Prevention Authority.
Brown, the former deputy chief of the Marin County Fire Department, was the point person for the county when PG&E began its wildfire camera program in 2018.
“The visuals during a developing fire have driven our operational response,” he said. “We’re able to be more strategic with where we deploy our resources.”
During the lightning stoked Woodward wildfire in Point Reyes National Seashore over the summer, for example, fire officials used the cameras to guide evacuations, Brown said.
Dennis Rodoni, president of the Board of Supervisors, said PG&E’s equipment provides
the utility with better localized weather information, which enables “better choices” about power shutoffs. He said the changes might eliminate massive shutoffs like the one in Marin in 2019.
Woody Baker-Cohn, assistant emergency manager of the Office of Emergency Services at the Marin County Sheriff’s Office, said while more data is helpful, more can be done to communicate planned outages and to power cellular towers so residents can still receive emergency alerts on their mobile devices.
PG&E has established a
public information website at pge.com/wildfiresafety. The utility has also installed at least 42 “sectionalizers” in Marin. The devices limit the size of outages by breaking the power grid into smaller sections allowing remote control of power lines.
In the fall, when the threat of shutoffs was heightened during the peak of fire season, generators were situated in San Rafael, Sausalito, Bolinas, Corte Madera, Inverness, Mill Valley and Novato to power substations.
Contreras said PG&E plans to increase its network
to 1,300 weather stations by the end of the year. That will help the utility achieve a density of roughly one weather station in every 20 miles of high fire threat area, she said.
The utility plans to have nearly 600 cameras installed by the end of 2022. This would provide access to view roughly 90% of the high fire risk area it serves, Contreras said.
The weather data and cameras are available to fire agencies. Information is available to the public at pge.com/weather and cameras are at alertwildfire. org/northbay.