Unrelenting September heat wave grips California and western U.S.

OAKLAND, Calif. - California and the western United States are immersed in a historically severe September heat wave that is predicted to intensify early this week. The record-breaking temperatures are stressing power grids, fueling fires and endangering health.

The prolonged heat wave began on Aug. 30 and is forecast to peak on Monday and Tuesday before gradually easing during the second half of the week. Dozens of high temperature records have already been broken from California to Montana and dozens more are forecast.

On Saturday, numerous cities in the Intermountain West endured their highest temperatures on record not only for Sept. 3 but for the entire month. Salt Lake City (which hit 103 degrees), Pocatello, Idaho, (102 degrees), and Great Falls, Mont. (102 degrees) were among them.

“This is the worst September heat wave in Western USA history no doubt,” tweeted Maximiliano Herrera, a world weather historian, on Saturday night.

In Death Valley, Calif., the temperature has topped 120 degrees on five straight days, and is predicted to come close to the world record September temperature of 126 degrees Tuesday.

Climate scientists have found human-caused climate change is increasing the intensity, frequency and duration of heat waves such as this one. Nearly 50 million people are under excessive heat warnings or heat advisories through the early part of the week from California to Idaho.

With temperatures forecast to soar into the 90s and 100s over much of the state Sunday, the California Independent System Operator (ISO), which oversees the power grid, issued the fifth consecutive “Flex Alert” calling for energy conservation between 4 p.m. and 9 p.m. to avoid outages. Demand on Thursday peaked at 47,357 megawatts, which was the highest load since September 2017, but usage fell a bit on Friday and Saturday.

“California consumers and businesses have responded to our Flex Alert calls with helpful reductions in their electricity use during the grid’s most challenging hours,” said California ISO chief executive Elliot Mainzer in a video update on Saturday. “Cooperation like this makes a real difference, so thank you everyone for that help.” The agency is bracing for peak demand on Tuesday of more than 50,000 megawatts.

The punishing heat has fueled numerous fast-moving fires. In far northern California, near the town of Weed, firefighters are battling the Mill and nearby Mountain fires. The Mill Fire, which was 25% contained Saturday evening, destroyed 50 structures, prompted evacuations and injured multiple people. Both fires started on Friday.

The Route Fire, which erupted Wednesday east of Los Angeles, burned more than 5,200 acres and at least eight firefighters suffered heat-related injuries battling the flames. By Sunday morning the blaze was 87% contained.

Numerous fires have also erupted in Oregon, whose billowing smoke plumes could be seen from the Geostationary Operational Environmental Satellite on Saturday. Oregon Democratic Gov. Kate Brown declared a state of emergency a week ago due to the fire threat.

The Predictive Services of the National Interagency Fire Center is warning of “high risk” conditions in many areas of California and the Mountain West.

In the coming days some of the most excessive heat is forecast in California’s Central Valley. Sacramento has already reached the century mark four days in a row and is forecast to see six more. The National Weather Service says it has a 67% chance to match its September record of 109 degrees on Tuesday.

People who have to work outdoors during the heat wave are at particular risk, and California Department of Industrial Relations issued an advisory earlier in the week reminding employers of their legal obligation to protect workers by providing adequate water, shade and rest.

Cynthia Burgos, a farmworker in Bakersfield - where it’s forecast to reach 111 degrees Tuesday - has plenty of experience working in the heat, harvesting carrots.

“By around 10 or 11 a.m., it is already very hot, and the humidity in the ground starts rising,” she said via a translator. “It’s just a miserable experience.”

Farmworkers have collapsed and even died in these conditions. On a day last year that surpassed 100 degrees, Burgos and her co-workers initiated a work stoppage because the only drinking water available was extremely hot. She is not working during this heat wave, because she has been on leave to campaign for a state bill that would expand union voting rights for farmworkers.

“It shouldn’t be the workers’ job - it’s the employers’ responsibility to provide a safe working environment,” said Elizabeth Strater from the United Farm Workers union. “The higher the heat gets, the more it seems like they’re giving up.”

In the Bay Area, coastal regions have seen cooler temperatures from the 60s to the low 80s, but inland cities have gotten up to the 90s, with several areas expected to hit over 100 for the next few days in a row. As a precaution, the East Bay Regional Park District is closing most of the area’s parks for Sunday and Monday, to limit the chances of visitors sparking a fire.

“What makes this heat wave different is the duration,” said meteorologist Sarah McCorkle from the National Weather Service San Francisco Bay area office. In some places, she said, 100 degree heat may last more than seven days, which is unusual. “It’s a marathon, not a sprint.”

In the East Bay city of Dublin, Calif., on Saturday afternoon, the temperature was in the mid-90s, and three members of the Ting family were about to head into the movie theater for two movies in a row.

“Yesterday we had two power outages - one in the middle of the night, and one during the day,” said Mike Ting. His wife, Nola Ting, teaches at a nearby elementary school that let out early on Friday due to a power outage. A national promotion offering cheap movie tickets for a day is what got the family to the theater, but they said they appreciate the air conditioning.

“Whenever it’s hot, it’s always fun to do something cool in the middle of the day,” said Mike Ting. “Hopefully things’ll get better soon.”

The heat has been relentless in Southern California since the middle of last week. Burbank soared to a 112 degrees Wednesday and has topped 100 every day since. On Saturday, even the typically mild San Diego set a record high of 95.

Los Angeles UPS driver Jared Hamil said he recorded a temperature of 131 degrees in the back of his truck on Friday. “It’s like being in an oven,” he said.

Hamil reports that his truck does not have air conditioning or a fan, and he sometimes has to spend several minutes in the back area looking for a package. In the near term, to help reduce the load on drivers on hot days, he proposes that the company send out more trucks and split routes into smaller chunks to give workers shorter days. He adds that in his experience, managers are not always understanding of accommodations people make for their health. “Stop harassing people when they take a cool-down break or go use the restroom,” he said.

Matthew O’Connor, the director of media relations for UPS, submitted a statement by email from the company asserting that “the health and safety of our employees is our highest priority.” He listed efforts the company is making during the heat wave to prevent employees from overheating, including providing water, ice, electrolyte beverages, fruit, wicking uniforms, and cooling towels, and stated that UPS is in the process of installing fans in vehicles.

Research meteorologist Alexander Gershunov from the Scripps Institution of Oceanography said heat waves have been getting more frequent and intense worldwide, and in California in particular, more humid.

“With higher humidity, temperatures don’t really drop that much at night,” he said. “And in terms of health impacts, that pretty much removes the nighttime respite that we need to face another day of scorching heat.”

He said these overall trends are not a surprise to researchers. Of all the extreme weather events, heat waves are “the most closely-related and directly-impacted by global warming.”

Samenow reported from Washington.