Wild weather electrifies region
Thunderstorms with lightning and gusty winds spark Bay Area fires — rolling blackouts expected to continue as heat wave strains power grid
The explosive combination of a heat wave and a rare summer thunderstorm battered Northern California on Sunday, fueling a swarm of wildfires as authorities warned that dry lightning strikes could kick up more blazes and that the sweltering weather could continue to bring rolling power shutoffs.
The National Weather Service issued a red flag warning for the Bay Area, indicating high fire threat, through 11 a.m Monday and was expecting more lightning into Monday morning. An excessive heat warning is also in effect through 9 p.m. Wednesday, after a scorching weekend in which temperatures in many areas hit the triple digits.
California’s electricity grid operator said that rolling power outages were likely in the afternoons and evenings through Wednesday, as air conditioners crank up and strain the power grid, even though no shutoffs were needed Sunday evening in Pacific Gas and Electric Co.’s service territory.
Moisture and abnormal wind patterns stemming from Tropical Storm Fausto, which is more than 1,000 miles south of San Francisco, combined with the atmospheric instability of a record heat wave to produce the onceinadecade lightning storm that started fires across the region, according to local meteorologists.
Isolated summer thunderstorms happen in the Bay Area nearly every year, but Jan Null, adjunct professor of meteorol
ogy at San Jose State University, can’t remember anything so extended or concentrated in nearly half a century. Moisture from the subtropics does not often reach as far north as the Bay Area, he said, and this time, the moisture arrived at the right temperature and humidity to create thunderstorms.
Daniel Swain, a climate scientist at UCLA and the National Center for Atmospheric Research, said extreme localized winds and heat bursts were part of the strangeness of the weekend. It was 80 degrees at Travis Air Force Base at 5 a.m. Sunday, and because of a rare compressional heating effect from the lightning storms, it was 100 degrees by 6.
“This was a Bay Areawide, multihour, severethunderstorm event,” Swain said. “It’s a pretty spectacular event.”
Northern California had 39 new fires Saturday night and into Sunday morning, according to Cal Fire, the state’s firefighting agency — though that figure is almost certainly a significant undercount. Some reached hundreds of acres, like the Marsh Fire, east of Milpitas near Arroyo Hondo Road, which had grown to 850 acres with zero containment by Sunday afternoon and forced the evacuation of 10 homes. A cluster of fires was burning about 400 acres in Contra Costa County southwest of Brentwood. Another, fastgrowing fire in Monterey County east of Salinas had reached 2,000 acres Sunday night and was threatening 30 structures, with mandatory evacuations in place.
Some fire departments on
Sunday morning asked residents to refrain from calling 911 when they smell smoke, to avoid inundating emergency lines.
“It seems like all of the cards are lining up for this to be a very uncommon event,” said Cal Fire Capt. Robert Foxworthy, who believes the erratic winds are the worst of the weather anomalies the region currently faces. “With the extended heat and incredibly high temperatures we have, along with throwing in the lightning that we’re getting, and you have to put those together with the dryness and prolonged drought that we’re in.”
On Sunday, Livermore reached 106 degrees, a record for Aug. 16. Other records for the date included Santa Rosa (103), San Jose (100), Santa Cruz (107) and Half Moon Bay (82). Death Valley hit its highest temperature ever in August, a blistering 130 degrees.
More 100plus temperatures are in the forecast for interior parts of the Bay Area through midweek.
“The highpressure system that’s bringing the hot weather is expected to stick around through the end of the week,” said Anna Schneider, a meteorologist for the National Weather Service.
The hot weather is badly straining California’s power grid, which has been forced to implement rolling outages in recent days. The California Independent System Operator asked residents to conserve energy between 3 and 10 p.m. each day, to help power plants meet demand.
“There is not a sufficient amount of energy to meet the high amounts of demand during the heat wave,” the system operator said Sunday.
Severin Borenstein, ISO board member and energy economist at UC Berkeley, said Monday will probably be the worst based on the weather forecast. He said the shutoffs are in part because of to the “crazy weather,” and people’s homes have not had time to cool down in the extreme temperatures so they turn the air condi
tioning on earlier.
Another part of it is the state’s growing reliance on solar energy. The outages have been occurring between 6 and 9 p.m.
“We are running a system with a lot of solar,” Borenstein said. “When solar goes away when the sun sets, we need other power. We have been rightly phasing out gas plants for very good reasons, but when you combine the lack of replacement for those with the crazy weather, we’re just in the situation where we’re going to be short.”
Borenstein added that the outages weren’t very large in comparison to the more widespread public safety shutoffs, in which PG&E and other utilities shut down power to high fire risk areas lest the equipment spark a blaze. But he said the issue is still serious.
Jeff Smith, a spokesman for PG&E, said the utility company is encouraging all customers to conserve as much power as possible for the next few days, and to prepare for the possibility of rolling blackouts. He said the utility gets only about 10 minutes notice from the state grid managers before the shutoffs must begin.
Energy conservation measures Californians can take include putting off certain chores — such as running washing machines — later in the week, Smith said. PG&E also asked customers to raise the temperature on their thermostats, cover windows, avoid using the oven and limit the number of times they open the refrigerator.
“Not only are we seeing really hot temperatures in the places where we normally see them, but we are also seeing them in areas that are typically much cooler during this time of year,” said Smith. “That’s what is really causing this (over) load.”
Rainfall totals from the storm have been low, less than a tenth of an inch in most of the region as of Sunday afternoon. Parts of the Santa Cruz Mountains and Mount Diablo, however, have seen close to a quarter inch.
That’s because the tropical moisture moving through the Bay Area is high (8,000 to 15,000 feet), while the region’s hot and stagnant air is closer to the Earth’s surface, according to Schneider of the weather service.
“There is a disconnect between the two,” she said. But she does expect the odd activity to diminish after Monday morning.
The Bay Area Air Quality Management District issued an air quality advisory because of the wildfires. Although the pollution, made of fine particles, was not expected to exceed the national 24hour standard, air quality could deteriorate in areas downwind of the fire, the agency warned.
Peak wind gusts early Sunday reached 75 mph, said Drew Peterson, a meteorologist with the National Weather Service. At Atlas Peak above the Napa Valley, gusts reached 66 mph, winds of 48 mph were recorded at Mount St. Helena, 45 mph at Mount Tamalpais and 42 mph at Mount Diablo, according to the weather service.