The heavy winds that downed power lines Sunday night at the start of the deadly wildfires raging across Northern California were far from “hurricane strength,” as PG&E has claimed, according to a review of weather station readings.
On Tuesday, the Bay Area News Group reported that Sonoma County emergency dispatchers sent fire crews to at least 10 reports of downed power lines and exploding transformers as the North Bay fires were starting around 9:22 p.m. In response, PG&E said that “hurricane strength winds in excess of 75 mph in some cases” had damaged their equipment, but they said it was too early to speculate what started the fires.
However, wind speeds were only about half that level, as the lines started to come down, the weather station records show. At a weather station in north Santa Rosa where the Tubbs Fire started, the wind gusts at 9:29 p.m. peaked at 30 mph. An hour later, they were 41 mph.
Similarly, at another weather station east of the city of Napa, on Atlas Peak, where the Atlas Fire started, wind gusts at 9:29 p.m. peaked at 32 mph. An hour later they were 30 mph.
Both speeds were substantially under the speed specified in state law: Power lines must be able to withstand winds of at least 56 mph.
“This is classic PG&E — trying to spin things without first taking a look at the hard facts,” said Burlingame attorney Frank Pitre. “The winds were well within the threshold of design standards. If they failed, this was a failure in their system.”
Investigators are looking at power line failures as a possible cause of the historic fires.
PG&E officials did not respond to specific questions Thursday about the wind speeds and whether their power lines were in compliance with state safety laws.
“There will likely be reviews of these wildfires by the appropriate agencies, but right now we are focused on life safety and service restoration,” said PG&E spokesman Donald Cutler.
Pitre sued PG&E after the utility was found responsible by the state Public Utilities Commission for starting the Butte Fire in Amador County in 2015 because of the utility’s failure to maintain its power lines. That fire burned for 22 days, killing two people, destroying 549 homes and charring 70,868 acres. The PUC fined PG&E $8.3 million and Cal Fire sent PG&E a bill for $90 million to cover state firefighting costs.
Meanwhile, the “hurricane strength winds” that PG&E referenced are not “hurricane strength,” according to the National Weather Service.
“It’s not a good analogy,” said National Weather Service meteorologist Roger Gass in Monterey.
To qualify as “hurricane strength,” winds must be sustained — lasting for more than 1 minute — at a minimum 74 mph. Such winds are the speeds in a Category 1 hurricane, the weakest of five categories.
In the Napa-Sonoma area, one weather station used by the National Weather Service, on Hawkeye Peak near Geyserville, recorded gusts of 79 mph at 11:56 pm on Sunday night. But gusts are defined as lasting only 3 to 5 seconds, and the sustained wind speed there at that time was 48 mph. Also, Hawkeye Peak is 22 miles north of Santa Rosa and 50 miles north of Napa, far from where the major fires broke out.
Under state law, utilities are required to maintain power lines safely and cut back trees to prevent fires. When they are found to have started fires, they are liable for fines and damages in court to people who have lost homes, businesses and family members in the blazes.
If PG&E is found to be at fault in this fire, the utility could use an “act of God” defense, arguing that weather conditions were so bad it couldn’t do anything to stop power lines from coming down.
“They could use that as a defense,” said Britt Strottman, an Oakland attorney representing victims in Calaveras County of the Butte Fire. “Then it will be up to the PUC and Cal Fire — along with any judge and juries in civil cases — to decide whether that holds water.”
In 1994, PG&E was found guilty of 739 counts of negligence and fined nearly $30 million by state regulators when trees touched its high-voltage wires in Nevada County in the Sierra foothills, sparking a fire near the town of Rough and Ready that destroyed 12 homes and a 19th century schoolhouse. Afterward, prosecutors found that PG&E had diverted nearly $80 million from its tree-cutting programs into profits.
“If PG&E is at fault or partially at fault for these fires, it could be devastating to the company,” Strottman said. “PG&E could face significant fines and penalties.”
The company was fined $1.6 billion by the PUC after it was found negligent in causing the 2010 San Bruno gas line explosion, which killed eight people and destroyed 38 homes.
Investigators continue to probe the cause of the more than 20 fires that are still burning across Northern California, killing at least 31 people, destroying more than 3,000 homes and charring 190,000 acres.
“There isn’t anything we can talk about because those are active investigations,” Cal Fire Chief Ken Pimlott said Thursday. “We all want to get to the bottom of what caused the fires. But at the end of the day, they need to do their job and we need to do the job of putting these fires out — and that’s going to be our focus.”
Despite strong winds this week, parts of the Napa and Sonoma valleys have experienced stronger winds this year. Atlas Peak had gusts of 66 mph last February, for example.
“It was a strong wind event, but not unprecedented,” said Jan Null, a meteorologist with Golden Gate Weather Services in Saratoga.
Strong wind storms commonly send trees into power poles, cutting off power to thousands of customers. But what was different on Sunday night was the time of year: In the winter, downed power lines don’t cause giant conflagrations.
“Trees and power lines go down in winter winds all the time,” he said. “But that’s on wet ground, not ground that is tinder dry.”
“We’ve had stronger wind events, but it was during a different time of year,” Null said. “This was a matter of everything lining up” to bring down poles and wires. “It was a very dry, warm wind from the northeast.”
“Should that happen? That is the overriding question,” Null said. “It’s not for me to say.”