What’s behind the hot temperatures? It’s called a heat dome: an atmospheric cap traps warm air over the western US, igniting intense heat. You can read more here about the science behind California’s worsening heat waves, as explained by the Chronicle’s weather science team. Our reporters are gearing up today to bring you the latest news from the Bay Area, and our meteorologist is ready to talk about what he sees ahead. Latest updates:
Don’t go to Stinson Beach, Marin officials warn “If you’re not already in Stinson Beach … we’d suggest you don’t go,” the Marin County Sheriff tweeted Sunday. “There are hour-long delays getting into the area and car parks and street parking are all full.” As of Sunday, the sheriff’s office said it had issued more than 145 citations in Stinson Beach. Visitors are asked not to block roads or park in yards and to be respectful of residents. If you’re not already at Stinson Beach… We suggest you don’t go. Expect long delays to get into the area and the car parks and street parking are all full. pic.twitter.com/1XMRE5qxPt — Marin County Sheriff (@MarinSheriff) September 5, 2022
California lawmakers want to crack down on heat waves
On Gov. Gavin Newsom’s desk is AB2238, a bill that would direct the state Environmental Protection Agency to create a ranking system for heat waves by 2025. Hurricanes, earthquakes and even atmospheric rivers are ranked by severity them — so why not heat waves? It’s unclear how the current heat wave will be classified, but officials say its extreme temperatures and long duration make it particularly dangerous. Read more here about the heat wave classification bill, which passed unanimously with bipartisan support.
Parking lots at Marin Beaches and near the Golden Gate Bridge area are full Golden Gate National Recreation Area said on Twitter that parking lots at Stinson Beach, Muir Beach and Rodeo Beach in Marin County are full, as are most of its San Francisco sites. “We welcome our visitors escaping the heat and remind them to be patient, stay in the shade and not risk cold ocean currents or coastal bluffs,” the park service tweeted. Dozens of beachgoers flocked to the Bay Area shore Saturday afternoon as temperatures began to rise ahead of an expected heat wave that has state officials worried about heat-related illnesses and potential wildfires. Greg Griffin/The Chronicle
Even San Francisco is already experiencing “extreme” heat
Heat in San Francisco is considered extreme when it exceeds 85 degrees — and just before noon, the reading downtown was already at 89 degrees. However, the city will remain cooler than most parts of the sweltering region and state.
The head of the network in California says that demand on Tuesday is expected to be higher than ever Amid sweltering temperatures across California, the state’s electric grid operator is predicting the highest power demand it has ever seen in the state’s history. Californians burned through 50,270 megawatts of power on July 24, 2006, but California Independent System Operator President and CEO Elliott Meinger said Monday at a news conference that expected demand has exceeded that record high for Tuesday. He urged Californians to keep their power on during the core hours of 4 p.m. until 10 p.m. this week and hoped those reductions and bringing in power from other states could get the state through Monday and Tuesday without back-to-back blackouts.
The California grid is issuing a Stage 1 Emergency Alert In a sign of the intense pressure on power supplies caused by the heat wave, California’s grid operator issued a Power Emergency 1 alert for Monday, effective from 5 p.m. until 9 p.m. This is the first Level 1 emergency alert for the grid so far this heatwave, and is designed to reduce energy demand from large customers and create more supply. If the grid goes through emergency stages 2 and 3 — which grid officials believe could happen Monday — then it’s time for rolling blackouts because demand, which spikes due to air conditioning use , exceeds the supply. Read more here about the near-unprecedented strain on California’s power grid.
Fire danger is high across California Officials are warning against any activity that could start a fire, as the extreme temperatures have further dried the vegetation and made it particularly vulnerable to a spark. Fire danger is rated high through Friday for most of California.
How long will the heat wave last? What seems like a never-ending heat wave peaks this Labor Day, with widespread temperatures of 105-110° F blanketing the North Bay, East Bay and Sacramento Valley. Even San Francisco is dealing with some of the heat as parts of the city soar into the 80s today. This historic heat wave isn’t done with California yet. With the heat wave expected to extend, all extreme heat warnings and advisories for the Bay Area and Sacramento Valley have been extended until 8 p.m. Thursday. Fans take advantage of the shade as they watch the San Francisco Giants play the Philadelphia Phillies at Oracle Park in San Francisco on Sunday. Scott Strazzante/The Chronicle
Hiker suffering from heat exhaustion rescued from Mount Montara
Officials rescued a hiker suffering from heat exhaustion on Mount Montara in San Mateo County on Sunday, according to a tweet from Cal Fire’s CZU branch. Read here about officials’ warnings about exercising outdoors this weekend, following a string of high-profile heat-related deaths over the past year. Coastside Fire Engine 44, @CAStateParks & @CHP rescued a hiker suffering from heat exhaustion Sunday on Montara Mountain. Waiting for more details…. 🚁 pic.twitter.com/GNii2RztLS — CAL FIRE CZU (@CALFIRECZU) September 5, 2022
Flex alert in effect Monday from 4 p.m. until 10 p.m
During this time, electric grid officials are asking Californians to refrain from using energy-intensive appliances such as dryers or dishwashers and to turn off unnecessary lights. They’re also asking people to keep their air conditioning at 78 degrees or higher during this time (pre-cooling your home before 4 p.m. is a good idea). This is the latest in a series of Flex alerts during the heat wave. A cyclist rides by Lake Merritt during the Labor Day weekend heat wave in Oakland. Michaela Vatcheva/Special to The Chronicle
A rolling blackout is possible on Monday
Power grid conditions are expected to worsen late Monday afternoon as air conditioners work overtime and demand for electricity soars. Grid officials are anticipating emergencies and will ask consumers and businesses to conserve power from 4 to 10 p.m. in an effort to avoid rolling blackouts. Read more here about why grid managers are so worried.
What is a heat wave? Heat waves are usually defined as unusually hot weather lasting more than two days. But what is considered unusual can vary in different geographic areas of California. For example, a high temperature of 95 degrees Fahrenheit might describe a typical summer day in the Central Valley. But those temperatures could be unbearable in San Francisco, where residents typically don’t have air conditioning. Weather experts take these differences into account when issuing extreme heat warnings. Go here to read more about the science of heat waves.
