Skip to main content

The context you need, when you need it

When news breaks, you need to understand what actually matters — and what to do about it. At Vox, our mission to help you make sense of the world has never been more vital. But we can’t do it on our own.

We rely on readers like you to fund our journalism. Will you support our work and become a Vox Member today?

Join now

California’s heat wave caused rolling blackouts for millions

Up to 4 million people were hit by “load interruptions” after power reserves fell below a critical threshold.

California power shutoff
California power shutoff
Rolling blackouts hit California on August 14 as temperatures soared into the triple digits.
Yichuan Cao/NurPhoto via Getty Images

Soaring temperatures in California spurred such an overwhelming surge in electricity use that the state’s grid operator had to cut off power to up to 4 million people Friday evening.

California Independent System Operator, the body that runs the electric grid for most of the state, initially asked customers to reduce electricity use between 3 pm and 10 pm by doing things like turning off lights and raising their thermostats to 78 degrees or higher.

But after power reserves fell below a critical threshold, the grid operator shifted to a “Stage 3” emergency and triggered “load interruptions” across the state starting around 6:30 pm.

The blackouts underscore how vulnerable the state’s electric grids are to being overwhelmed precisely when people lean on them most for safety and comfort in extreme weather.

Most of the West Coast was under heat alerts on Friday, the first day of an extraordinary heat wave that is expected to continue through the middle of next week and push parts of California into the triple digits.

The state’s utilities began to cut off customers, at least some of the time without advance notice, for brief outages. The state’s biggest utility, PG&E said that the outages occurred for 60 to 90 minutes on a rotating basis in its northern and central California territory, according to Bloomberg News.

The blackouts were the largest in the state since “public safety power shutoffs” in the state last fall, when dry, windy weather conditions prompted PG&E to cut off electricity to hundreds of thousands of people for several days at a time. Vox’s David Roberts described the poorly organized blackouts, which put vulnerable populations at risk and caused chaos for vital services like hospitals and law enforcement, as “absolutely bonkers.”

The weather isn’t getting better for a while

Meteorologists say California — and much of the rest of the country — is in for a rough time with the heatwave that kicked off on Friday.

“A very intense and prolonged heatwave now appears likely for a large portion of California over the next 7-10 days, and this event will likely have wide-ranging impacts from human health, wildfire, and electricity demand perspectives,” wrote Daniel Swain, a climate scientists at the University of California Los Angeles on Friday. “I suspect this event will probably end up being one of the most significant widespread California extreme heat events in the past decade, if not longer.”

Parts of Arizona, California, and Nevada are expected to reach highs of 110 to 125 degrees during a heat wave expected to last through Wednesday of next week.

“The longevity of the heat is more concerning than the record-breaking temperatures,” National Weather Service meteorologist Trevor Boucher told NBC News.

In 2001, California experienced a series of rolling blackouts, in part because of electricity shortages — but also in part because of “unscrupulous energy traders from companies like Enron ‘gaming’ a badly-flawed grid system and deliberately withholding electricity from California to extort higher prices,” according to the Sacramento Bee.

Grid operators say they’re prepared for future outages, but the likelihood of them over the weekend is smaller because demand shrinks outside of the workday.


Will you become our 20,000th supporter? When the economy took a downturn in the spring and we started asking readers for financial contributions, we weren’t sure how it would go. Today, we’re humbled to say that nearly 20,000 people have chipped in. The reason is both lovely and surprising: Readers told us that they contribute both because they value explanation and because they value that other people can access it, too. We have always believed that explanatory journalism is vital for a functioning democracy. That’s never been more important than today, during a public health crisis, racial justice protests, a recession, and a presidential election. But our distinctive explanatory journalism is expensive, and advertising alone won’t let us keep creating it at the quality and volume this moment requires. Your financial contribution will not constitute a donation, but it will help keep Vox free for all. Contribute today from as little as $3.

See More:

More in Climate

Climate
Why the American Southeast is becoming a new hot spot for wildfiresWhy the American Southeast is becoming a new hot spot for wildfires
Climate

“Weather whiplash” is fueling blazes across Florida and the region.

By Kiley Price
Climate
The climate crisis is coming for your groceriesThe climate crisis is coming for your groceries
Climate

Extreme heat is already wiping out soy, coffee, berries, and Christmas trees. Farm animals and humans are suffering too.

By Ayurella Horn-Muller
Future Perfect
“I’m disgusted to be a human”: What to do when you hate your own species“I’m disgusted to be a human”: What to do when you hate your own species
Future Perfect

Yes, it hurts to be human right now. That’s actually the assignment.

By Sigal Samuel
Climate
Levees can no longer save New OrleansLevees can no longer save New Orleans
Climate

The city is part of “the most physically vulnerable coastline in the world.”

By Oliver Milman
Future Perfect
The old tech that could help stop the next airborne pandemicThe old tech that could help stop the next airborne pandemic
Future Perfect

Glycol vapors, explained.

By Shayna Korol
Climate
The exploding costs of fighting US wildfiresThe exploding costs of fighting US wildfires
Climate

From taxes on nicotine to hotel rooms, states are looking for ways to pay the skyrocketing bill.

By Kylie Mohr