Update, 10 p.m. Widespread rolling blackouts were ultimately averted for California’s power grid Tuesday evening even though peak demand hit a new all-time record.

Original story, 5 p.m. As the state continues sizzling, temperatures topped out at 96 degrees Tuesday afternoon in Downtown Berkeley and 106 at Berkeley Lab in the hills. Residents were warned to be alert to dangerous heat, elevated pollution and the possibility of rolling blackouts as energy demand threatens to overwhelm California’s power grid. 

The California Independent Systems Operator, which oversees the grid, issued its seventh Flex Alert in a row Tuesday — urging people to voluntarily save power from 4 p.m. to 10 p.m.

It also declared a Stage 2 Energy Emergency Alert for 4 p.m. to 9 p.m., the last step before blackouts. The “hottest weather of this historic heat wave is forecast to push electricity demand to an all-time high,” the ISO said. 

Credit: California ISO

The ISO is currently expecting to declare a Stage 3 emergency at around 5:30 p.m. Tuesday, which would trigger rotating blackouts across California to reduce demand and prevent any single neighborhood from being down for very long. PG&E is warning its customers that blackouts lasting one to two hours “with little notice” are a possibility Tuesday. 

PG&E has an online lookup tool showing blocks where outages are expected. Some addresses in Berkeley are listed in the tool. 

“Rotating power outages” last occurred in California on Aug. 14, 2020, and Aug. 15, 2020, but did not affect Berkeley. Before 2020, it had been nearly two decades since outages were imposed due to energy shortages. The ISO describes these outages as “relatively short power disruptions” that help stretch available energy when supplies are short. 

The National Weather Service’s excessive heat warning, which applies to most of the Bay Area, lasts until 8 p.m. Tuesday. After that, it’ll be downgraded to just a heat advisory, which remains in effect until 8 p.m. Thursday. The NWS is urging people to avoid being outdoors during the morning and afternoon, use air conditioning if available and cancel daytime outdoor activities.

A Spare the Air alert for high concentrations of smog remains in effect through Wednesday, Sept. 7. People are urged to limit driving and work remotely if possible, as exposure to smog may cause respiratory irritation, make it more difficult to breathe and aggravate asthma, according to the Bay Area Air Quality Management District, which issued the alerts throughout Labor Day weekend. 

The current heat wave has been hotter — and longer — than previously forecasted. Originally, temperatures in the Berkeley flats were forecasted to peak at 85 degrees Sunday, and the heat wave forecasted to end on Wednesday. Heat advisories for the entire region have since been extended.

The National Weather Service forecasts lower temperatures for the remainder of the week. 

City’s cooling center opens for the first time since 2021

Berkeley opened the Emergency Cooling Center at the city’s emergency homeless shelter in Old City Hall from 11 a.m. to 7 p.m. on Tuesday. 

A Dorothy Day House staff member at the shelter, which is operated by the nonprofit, said the organization did outreach to homeless residents on Tuesday to notify them about the cooling shelter.

He said most of the people they contacted opted to go to local libraries instead because they have air conditioning. The cooling shelter currently doesn’t have fans or air conditioning, and no one had arrived for intake as of 2:30 p.m.

At the Berkeley Public Library on Kittredge Street, several people read and relaxed in the large community meeting room on Tuesday afternoon. All public libraries in Berkeley are open from 10 a.m. to 6 p.m. through Saturday. The South Berkeley Senior Center on 2929 Ellis St. is also open to residents aged 55 and older. 

As the heat wave continues, Alameda County Healthcare for the Homeless is urging service organizations to do on-the-ground outreach at street and encampment sites, and conduct wellness sites. Organizations who want information on accessing bottled water to distribute can contact the county at achch@acgov.org.

A full list of cooling centers throughout the county is available online

The National Weather Service offers the following preparation advice for heat waves:

  • Monitor the latest forecasts and warnings for updates on this situation. Be prepared to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check on relatives and neighbors. 
  • Young children and pets should never be left unattended in vehicles. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in minutes.
  • Take extra precautions if you work or spend time outside, and, if possible, reschedule strenuous activities to early morning or evening. To reduce risk during outdoor work, the state Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments. Anyone overcome by heat should be moved to a cool and shady location. Call 911 if someone is experiencing a heat stroke. 

PG&E offers this advice for power outage preparation:

  • Have a flashlight, radios, and fresh batteries ready. For more information on how to prepare for an emergency, visit PG&E’s Safety Action Center.
  • Use cooling centers to stay cool or during a power outage. Check with your city or county, or the Governor’s Office of Emergency Services list and map of cooling centers statewide.
  • Operate personal generators safely. Follow the owner’s manual and perform a visual inspection before starting or operating a generator. When setting up a generator, place it on a flat, stable surface to reduce the likelihood of it tipping over. To prevent carbon monoxide poisoning, never operate an engine-powered generator in an enclosed space or inside a house or a tent.

The California ISO offers this advice for energy conservation before a Flex Alert:

  • Pre-cool home by setting the thermostat to as low as 72 degrees
  • Use major appliances:
    • Washer and dryer
    • Dishwasher
    • Oven and stove for pre-cooking and preparing meals
  • Adjust blinds and drapes to cover windows

During a Flex Alert, the ISO recommends you:

  • Set the thermostat to 78 degrees or higher, if health permits
  • Avoid using major appliances
  • Turn off all unnecessary lights

Featured photo: Jerome Paulos

Iris Kwok covers the environment for Berkeleyside through a partnership with Report for America. A former music journalist, her work has appeared in the San Francisco Chronicle, KQED, San Francisco Examiner...

Supriya Yelimeli is a housing and homelessness reporter for Berkeleyside and joined the staff in May 2020 after contributing reporting since 2018 as a freelance writer. Yelimeli grew up in Fremont and...