California Fire Weather Triggers Major Utilities to Shut Off Power

Extremely critical fire weather threats were in effect for California on Oct 15. Unseasonably warm temperatures, very dry fuels and low humidity are contributing to the threats, but the main concern is very strong Santa Ana winds.National Weather Service

Extremely critical fire weather with strong wind and low humidity swept has California, triggering red flag warnings as well as prompting major utility companies to temporarily shut down power in certain areas to lower the risk of catching wildfire.

Pacific Gas and Electric (PG&E), one of the largest power suppliers across the nation and mainly covers Northern and Central California, announced Sunday night that around 60,000 of their customers were without power due to wind gusts with speeds up to 50 miles per hour.

The affected population included about 17,483 customers from Lake, Napa and Sonoma counties in Northern California as well as around 42,000 customers from the Sierra Foothills in Amador, El Dorado and Calaveras counties in Central California.

PG&E said in a statement that “strong winds, very low humidity levels, critically dry vegetation and on-the-ground observations” were the factors that led to the “Public Safety Power Shutoff.” The utility company was reportedly reluctant to resort such a strategy in the past as the outage might affect the police, firefighters, and hospitals. But things changed after the deadly wildfires in 2017.

In May 2018, Cal Fire alleged that three wildfires of the 2017 Northern California firestorm, which burned more than 245,000 acres and killed 44 people in Northern California, were ignited by PG&E power lines making contact with trees nearby.

California now requires utility companies to be responsible for fires linked to their equipment, no matter if they were complying with regulations or not. According to Reuters, there are about 200 lawsuits against PG&E related to the 2017 fires. The company could face costs of up to billions of dollars.

Although the sudden emergency power outage affected residents and businesses, PG&E is not the only supplier to use this strategy. San Diego Gas & Electric (SDG&E), which serves about 3.3 million consumers in San Diego and part of Orange County, also shut off power supply in certain areas.

In a statement from SDG&E, the Santa Ana winds, which feature high-speed gusts and low humidity, drastically worsened the fire conditions in some areas with dry vegetation. Around 2,000 customers were affected by the power outage.

A red flag warning issued by the National Weather Service (NWS) for most of Los Angeles County will last until late Tuesday.

“A combination of strong winds, low relative humidity and warm temperatures can contribute to extreme fire behavior,” warned the NWS station.

To deal with the extreme fire weather, Southern California Edison (SCE) also stated that a similar power shut off strategy could be deployed when the risk runs high. A power outage alert from SCE warning customers of the possibility of a power outage was sent out to customers in 41 cities of Los Angeles, Orange, Ventura and San Bernadino Counties, according to ABC 7.