SAN FRANCISCO (KPIX) -- The sprinkling of rain on Sunday night proved too much for some Bay Area power lines. The first rainfall of the autumn season caused multiple PG&E power poles to catch fire, in a phenomenon the company has dubbed "electrical flashover."
Sunday night's cold front brought only a light drizzle, with much of the region seeing trace amounts of precipitation in the late evening.
By 8pm, power poles inexplicably began catching fire, from San Francisco to Pleasanton. Residents captured and shared the fires on social media. In most instances, first responders arrived quickly to douse the flames. Wind caused red, hot embers to drift down into the street below, causing minor spot fires.
The vicinity near Jutland Street in San Leandro was hit especially hard, with at least 4 to 5 incidents within several blocks of one another.
Maeden Tantingco recalls hearing an explosion coming from the pole in front of her home.
"It's like a 'boom' and after that our power went out," said Tantingco. "Of course I was scared. We were like, 'it might blow up.'"
As of 12pm Monday afternoon, the Tantingco's power still had not been restored, and the family was eating a lunch of cold rice and adobo chicken, with food at risk of spoiling in the refrigerator.
At 9pm Sunday, the Alameda County Fire Department sent a tweet saying "The past hour your ACFD firefighters have been kept very busy responding to electrical pole fires due to the rain", showing multiple addresses across the county.
PG&E released a statement Sunday night:
After a long time without rain, dust, dirt, salt, and other substances accumulate on power lines. When the first mist or rain arrives after a long dry spell, it turns this mixture into mud, which conducts electricity. This can damage electrical equipment and potentially result in what's called electrical flashovers, or tracking (electricity finding another track or an alternate path instead of the wire), and therefore could cause power outages.
Other causes of weather-related damage include arcing. When there is enough dust and particulate in the air near power lines, it can create an arc and an electrical flashover.
PG&E does have a line washing program in place to keep its larger electric transmission lines clean, so these types of outages tend to impact the distribution system serving local neighborhoods.
Customers without power Sunday night:
October 17, 2021 - 10 pm
Bay Area Total
PG&E did not respond to requests for total number of power poles burned Sunday night, or the locations of the damaged poles.
The news of Sunday night's wet power pole fires is the latest development in more than a decade of tragedies and disasters, dating back to the 2010 San Bruno Pipeline explosion, and sparking 1500 wildfires in the past six years, including the Camp Fire, which killed 85 people and destroyed 18,800 structures. The Camp Fire is the largest and most destructive in California history.
Patricia, a neighbor on Drake Avenue in San Leandro, heard a strange noise Sunday night, and came out to see the power pole in front of her home ablaze. The longtime resident recalled PG&E crews periodically cleaning the power lines over the years and called the blaming of mud as the cause of the power pole fires as "crazy".
"Somewhere along the line we have to get some really smart people that say enough is enough, let's fix this problem, we know this is a problem," said Patricia.
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