California wildfires: Cell companies can't promise indefinite service
If a wildfire breaks out, your cell phone service may not work when you most need it.
Most cell stations in California have backup options, like batteries and generators. However, some major cell phone carriers told the Federal Communications Commission in filings this week that if physical access to cell towers is cut off, they can't guarantee service.
Backup power options "are not effective for mitigating the disruption to wireless communications when our facilities are damaged by fire," AT&T told the FCC.
Verizon said some of its sites in California don't have backup generators due to zoning and other restrictions, so the company will use portable generators that can be refueled. But whether to refuel a generator during a wildfire depends on access to the area, the safety of workers and the potential impact of wildfire, the company said.
"If (sites) lose commercial power, batteries kick in. If commercial power is lost for longer than the life span of the battery, the generator will kick in. We have a refueling plan for the generators if there's a prolonged outage," Verizon spokeswoman Heidi Flato said. "If there's an active wildfire, we don't always have access to the site, and that may impinge on our refueling plans."
Phone companies say they're prepared for Pacific Gas & Electric Co. power shutoffs, planned as a means to prevent the utility's lines from sparking wildfires. But if a fire breaks out, it may be a different story.
"When there is a disaster, the first thing that goes down is the network," said Chaitan Baru, a University of California San Diego data science researcher and adviser at the National Science Foundation. "Just when you need it, the cell phones are not working."
Many people get evacuation alerts via cell phones, and they also use them to make 911 calls. First responders find people needing help and often communicate with each other via cell phone.
The FCC had asked the companies to tell them how they would manage during shutoffs and wildfires. The California Public Utilities Commission, which regulates utilities and telephone companies in the state, is also watching: It's concerned about rural call failures after the devastating Camp Fire last year in Butte County.
During the Camp Fire, "we lost 17 cell towers," said Cindi Dunsmoor, emergency services officer for Butte County, triggering a communication problem. But during a PG&E shutoff that began Monday at 5 p.m. and lasted into Tuesday — with no wildfire — she received no complaints about cell service.
CPUC spokeswoman Constance Gordon said a shutoff typically doesn't prohibit access to any particular cell site.
In their filings with the FCC, most of the five major cell carriers — AT&T, Verizon, T-Mobile, U.S. Cellular and Sprint — stressed that they are prepared for shutoffs and wildfires. Besides having backup generators at most sites, they also have mobile cells they can roll to a hot spot in an emergency.
"Backup is important, but we need to have a fast restoration," said Nambirajan Seshadri, an engineering professor at UC San Diego and a former Broadcom executive. If all cell towers are taken out, he said, mobile cell sites and drones are better options.
Multiple cell phone companies emphasized that PG&E must give them adequate notice and an outline of the affected service area. PG&E spokesman Denny Boyles said the company will reach out to key contacts to let them know about potential power outages.
"We will make every attempt to advise public safety authorities, first responders, local municipalities and critical service providers in advance of notifying customers of Public Safety Power Shutoffs," Boyles said in an email. "Cell phone companies are included in the list of critical service providers."
AT&T said about 78% of its California sites have a built-in generator, hydrogen fuel cell backup power, or are engineered so a generator can quickly connect to them. This gives them 72 to 120 hours of backup power.
In disasters, AT&T uses extended-life batteries and portable generators, and if cell sites stop working, the company deploys portable sites that depend on an independent power source. In November, AT&T told the FCC that it refueled and staged generators in advance and recharged them after a disaster event.
Verizon said its battery backup on sites provides eight hours of power. Diesel generators offer between 24 and 72 hours of backup power on a single tank of fuel. For critical sites without permanent generators, Verizon deploys a fleet of mobile cells similar to AT&T. The company also has an emergency response team and sets up wireless communication centers for first responders with free Wi-Fi, tablets and charging stations.
T-Mobile said it has permanent generator backup power in "numerous strategic cell sites," including in rural areas. The company also makes Wi-Fi available at evacuation centers and disaster response zones and has waived payment fees for customers in wildfire-affected area codes.
Many of Sprint's cell sites are equipped with backup batteries which generally provide an average of seven hours of power, the company told the FCC. Within the U.S., in areas where space is sufficient and air quality regulations permit, Sprint installs fixed generators. A spokeswoman did not respond immediately to a question about whether any of those were in California.
U.S. Cellular said fixed or portable backup power covers 97% of potentially impacted areas. Its 79 sites in potential power shutoff areas rely on commercial power and have battery backup resources in place, and 49 of those sites also have backup generators. The company also said it has 14 portable backup generators in the vicinity of its northern California market, though none are in the Bay Area.
"We believe we are prepared to address any potential planned outages that occur as a result of California utility shutdown plans," U.S. Cellular's filing with the FCC said. "As in all emergency scenarios, our ability to operate on backup power indefinitely will be contingent upon continued access to fuel as well as the ability to safely access sites to complete refueling without endangering our associates, contractors or the public in general."
Even if there is cell service in an emergency, past Chronicle investigations have found that emergency alerts failed to reach a majority of residents during the 2017 Tubbs Fire that burned into Santa Rosa. However, that was because relatively few Sonoma County residents had enrolled and just 15% of warning calls were answered. The system wasn't deployed in the 2018 Camp Fire. The fires combined killed more than 100 people.
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