When Hurricane Harvey lashed out at Texas and Louisiana last week, the wireless networks stood their ground.
Cellular service held up better during Harvey than in past storms, which is surprising given the scope and size of the disaster. Harvey devastated hundreds of miles of coastline from Corpus Christi, Texas, to Lake Charles, Louisiana. The flooding covers an area that's roughly the size of Lake Michigan and is home to more than 4.5 million people. A week after the storm first made landfall in Texas, waters are receding, but some roads are still impassable.
Not every area's cell coverage fared well. In the four counties along the Texas Gulf Coast where the hurricane first made landfall, there were significant outages, leaving tens of thousands of people without phone service. Last weekend in the immediate aftermath of the hurricane, Aransas County in Texas reported nearly 95 percent of its cell towers were out of commission, according to the Federal Communications Commission.
But across the entire affected area, cell networks did relatively well, thanks in part to the lessons the carriers have learned from dealing with past disasters. It's increasingly critical that cell service works during times of disaster; fewer people have landlines, and they rely on a smartphone for many things beyond a simple phone call. When disaster strikes, you don't want to be stuck listening to a busy signal.
By contrast, just 4 percent of the 7,804 cell sites in Harvey's path experienced outages during the storm, according to the FCC. That's less than 400 cell towers.
"For a disaster of this scope, to only have 4 percent of cell sites go down is really amazing in some ways," said Jamie Barnett, a partner at law firm Venable and a former chief of the FCC's Public Safety and Homeland Security Bureau.
Still, some critics say it's too early to pat the carriers on the back.
"We need to find out what happened there; people's lives depend on it," Regina Costa said of the affected cell towers. Costa is chair of the telecommunications committee of the National Association of State Utility Advocates, an organization that represents consumer interests on public utility matters.
What went right
While the four counties where Harvey made landfall took the brunt of the devastation from a cellular coverage perspective, wireless carriers have worked quickly to restore service. By Wednesday, carriers had cut the number of downed cell towers by half.
Experts like Barnett say it seems wireless carriers learned some lessons from previous disasters and prepared for the hurricane. For instance, AT&T and Verizon made sure to top off fuel in backup generators at cell sites, according to the companies. They staged refueling trucks in predetermined sites near the affected area to ensure they could get out after the storm passed to refuel those generators in case commercial power was lost. This was a major issue in previous storms, like Katrina, where cell sites that had backup power ran out of fuel.
All the major carriers readied portable cell towers called COWS (cell sites on wheels) that could be deployed in areas where permanent cell towers sustained damage. And in cases when the fiber lines connecting the cell towers to the carrier's wired network were damaged, Verizon said it has been able to set up temporary microwave links to complete the connection over the air.
The carriers are also taking measures to recover more quickly from the storm. AT&T and Verizon have each deployed drones to fly over the area to assess damage to cell towers. Using drones is not only safer and faster than sending a tower climbing crew, but it also allows the carriers to access sites that are inaccessible due to flooding, said Karen Schulz, a Verizon spokeswoman.
When the drones do the inspections, they're looking for things like cracked antennae, frayed coax cable or other issues that may be causing a problem now or may result in service interruptions in the coming days.
Carriers have also made fundamental changes to their networks that may make the networks more resilient. One example is small cell technology that reduces the size of the cell sites. That makes networks more resilient because traffic can be handed off more easily to sites that haven't been damaged.
Another key lesson was the need for wireless carriers to work together and share infrastructure to ensure all wireless customers had access to service regardless of carrier. That's helpful if one carrier's equipment goes down.
In December 2016, the FCC adopted a Mobile Wireless Resiliency Order in response to Superstorm Sandy. It sets up a protocol for carriers to broaden roaming during disasters and fosters mutual aid among wireless carriers during emergencies. All the major wireless carriers voluntarily signed on to the agreement.
"All of this seems to be helping," Barnett said.
It's all about power
But is it enough? Consumer advocate Costa says no.
There were, after all, the outages where Harvey made landfall. Costa says the FCC needs to take a close look at which carriers were involved in the outages and figure out the root cause.
One area that was problematic in past disasters and has likely played a role in the outages from Harvey has to do with a lack of power at cell towers. When the commercial power grid goes down, as often happens during these disasters, communications are cut off unless there's a backup.
Wireless carriers say many cell sites have generators that kick into action when commercial power is lost, but there's no regulatory requirement that mandates how much of that infrastructure must have backups. There's also no requirement that this infrastructure be maintained. Companies don't even need to disclose to the FCC or the public how much of their infrastructure has backups, let alone details on which towers have generators.
"We can't simply take the word of the wireless carriers at face value that they were adequately prepared," Costa said. "We must verify."
Costa said a full review is needed to determine why sites failed.
"We learned from Katrina and Sandy, and we need to learn from Harvey," she said. "Did backup power fail and cause these outages? Or did it fail because of storm damage to the equipment?"
It's not just for storms. The infrastructure's reliance on commercial power is a liability during other natural disasters, or even cyberattacks, she said.
"Not all parts of the infrastructure are created equal," Costa said. "Carriers pick and choose where to put these backups. I don't think you can conclude that everything is hunky-dory until the carriers identify what happened and why."
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