UPDATE: Widespread phone service outage caused by damage to AT&T fiber

An AT&T outage map as of about 10:30 a.m. Thursday showed areas in Tuolumne and Calaveras counties affected by a prolonged outage that began between about 4 and 5 p.m. Wednesday.

A widespread AT&T outage that began Wednesday afternoon and left many Tuolumne County residents with little to no cell phone service or the ability to call 911 for more than 18 hours was caused by unspecified damage to the company's fiber-optic line, an AT&T spokesperson confirmed.

In response to questions from The Union Democrat sent Thursday morning, the spokesperson provided a written statement at 12:39 p.m. that read: "We have completed repairs and restored service to a small number of customers in the Tuolumne County area following damage to our fiber by a third party."

The website Downdetector.com, which tracks phone outages reported by users, showed that reports about the Tuolumne County outage began between 4 and 5 p.m. Wednesday and peaked about 7 p.m. that night.

Verizon and T-Mobile customers in the county were also experiencing little to no service.

At least two previous AT&T outages in 2014 and 2019 have affected multiple carriers, including Verizon, because it leased access to AT&T fiber-optic lines in the area that were damaged in both previous instances.

AT&T’s online outage map at 10:30 a.m. Thursday showed outages in every ZIP code in Tuolumne County, as well as San Andreas, Angels Camp, Vallecito, Hathaway Pines and Avery in Calaveras County.

The map indicated the outage was affecting both landline and wireless services. Causes listed in different areas included “equipment failure,” “transport failure,” and “not known at this time.”

No estimated restoration time was provided for most of the affected areas, though the map stated that wireless services in the Sonora area were expected to be back up by 9:02 a.m.

However, AT&T customers in Sonora were still without service as of about 10:10 a.m., and the company switched the estimated restoration time to “Not known at this time.”

Some unable to use 911

Some people were also reportedly unable to call 911 due to the prolonged outage, presenting a serious safety concern.

Both the Tuolumne County Sheriff’s Office and Sonora Police Department released statements on the situation Wednesday night and provided alternate numbers for people to reach them in an emergency if 911 wasn’t working.

“Please be advised Tuolumne County cellular networks are experiencing a widespread outage affecting various network's ability to call/receive calls and affecting the ability to call 911,” the Sheriff’s Office stated at 7:22 p.m. Wednesday. “We are unsure what is causing the outage and have been in contact with providers who are working to fix the issue.”

The Sheriff’s Office stated that it was receiving calls intermittently due to its phone lines also being affected by the outage.

Sheriff’s Investigator Ashley Boujikian stated at 10:15 a.m. Thursday that the agency had yet to receive any verified information from AT&T that it could relay.

Anyone experiencing an emergency and cannot reach 911 was asked to try calling the Sheriff’s Office at (209) 532-2654. They could also try the non-emergency line at (209) 533-5815.

The Sheriff’s Office provided an update at 9:21 a.m. Thursday that included the following additional alternate numbers people could call if 911 wasn’t working:

• (209) 213-9186

• (209) 768-3666

• (209) 770-6969

• (916) 912-4685 and enter code 46101 or 46102

Previous AT&T outages led to lengthy service blackouts

This isn’t the first time that an outage involving AT&T equipment has caused widespread problems with telecommunications throughout the county.

In October 2014, thousands of Mother Lode residents were left without telephone or internet service for hours due to a widespread outage caused by an AT&T fiber-optic cable in Sonora being deliberately cut.

The 2014 outage forced 911 calls to be routed through outside counties, disabled some ATMs and stop lights, cut off AT&T high-speed internet service and affected the ability of people to make and receive calls via both landline and cellular devices from multiple carriers that used the AT&T line to transmit their signals.

A fallen tree was initially cited by AT&T as the cause of the damage to the line in the 2014 outage, but it was later declared a criminal act by former county Sheriff Jim Mele after deputies he sent to investigate determined the line had been deliberately cut.

No arrests were ever made in connection with the 2014 outage. AT&T blamed the false information about the fallen tree on miscommunication between its field workers and Bay Area press office.

A Verizon spokeswoman at the time explained to The Union Democrat how wireless networks interconnect with landline telecommunication services through fiber-optic cables like the one that was damaged. Any damage to the cables can cause an interruption of service and complete shut-down of phone lines.

A similar mass telephone and internet outage occurred nearly five years later in March 2019, when Caltrans paving subcontractors accidentally struck and damaged an underground AT&T fiber-optic line in the Clements area.

The same Verizon spokeswoman said the company's service was also affected by both of the previous outages because it leased access to the damaged AT&T's fiber-optic lines.

Contact Alex MacLean at [email protected] or (209) 588-4541.